This morning I woke up to a tweet from Bryn Humberstone.

Today’s date is a Pythagorean triple (written as 15/8/17 or 8/15/17). To ponder: How long until the next one? #iteachmath #MTBoS

— Bryn Humberstone (@brynhumberstone) August 14, 2017

I love using topical moments — like today’s date — as a lesson starter. While I understand the fatigue that days like Pi Day (14 March) can cause, I think it can be a great opportunity to briefly introduce some maths that might not be in the lesson plan. (Sara Van Der Werf has a recent and positive blog post on math(s) holidays that you should read.) Plus, I like my students to witness the joy I have in mathsy moments — even if they think I’m weird!

After the tweet, I opened my email to this image from brilliant.org and the 100 Day Summer Challenge.

To top it off, my plan for today’s #math1070 class was to review last week’s task: choose one of the four images below and tell me what you Notice and Wonder about it. You might be able to see how my lesson starter was going to unfold!

I started with today’s date: 15/8/17. I said it was an interesting mathematical date. Could anyone work out why? I then showed this image. We had a quick refresher of the Pythagorean theorem. This image already throws up some interesting questions: is it possible to always colour the squares on the hypotenuse with a complete square of one colour and a double thickness ‘half-border’ of the other?

Next, I showed the image from brilliant.org. I was careful to draw the squares on the sides of the 3-4-5 triangle, and connect Pythagoras’ theorem to the area of the squares that can be drawn on each side of the triangle. Then I asked them what they noticed and wondered. What do you notice and wonder? We had a little discussion based on this prompt, including generalising the side lengths.

Finally, I showed the image from their weekly task. Those who chose this image as their prompt generated a lot of noticings and wonderings; they are at the bottom of this post. For now, I directed their attention to the number of isosceles trapeziums making up the larger trapeziums on each side. The counts are 9, 16 and 25. What do you wonder now?

We explored whether this was a 3-4-5 triangle (it is) using the long base of the smaller trapezium as one unit. The overwhelming question in the room was why Pythagoras’ Theorem works for non-square shapes. I acknowledged that it works for similar shapes, and left it there. (By now, the lesson starter was threatening to take over the lesson!)

I finished with a quote from Chapter 7 of Tracy Zager’s book, from Peter Hilton: ** “Computation involves going from a question to an answer. Mathematics involves going from an answer to a question.” **I hope that these images and initial discussion prompted many more questions that they could go on to explore in their own time.

Incidentally, it was another serendipitous find this morning, shared on Twitter by John Golden, that sharply reminded me of this quote. John shared this blog post by Pat Ciula. It uses the same trapezium image to launch a complete different exploration. I love this post; do check it out for yourself.

This wasn’t really what I had planned for today’s class, but when these moments come along, you need to grab them!

These are from last week’s task, submitted in advance of today’s class. I’ve made some minor edits.

**I notice (that) …**

- Different colours are used: red and pink.
- A triangle has been made in the middle.
- The triangle formed is a right-angled triangle.
- All three shapes are the same.
- All three shapes are made up of smaller versions of the overall shape.
- The shapes are created by wooden blocks all put together.
- Each individual piece is a trapezium.
- There are three larger trapeziums made out of individual tessellating trapeziums.
- That the four-sided polygons go in an anti-clockwise movement ranging from smallest to largest.
- The blocks are arranged in different ways in each trapezium.
- The three trapezoids are similar trapezoids.
- There are nine sides forming the outer perimeter of the shape.
- In the centre of the three larger trapezium shapes, the points of the bases of these shapes make a right-angled triangle.
- If you were to move the largest trapezium shape so it was opposite where it is now, the shape in the middle made by the sides of the trapeziums would still be a triangle.
- Each tile is the same shape – trapezoids. In each tile, three sides (top and the two edges) are equal, and the base (the longest side) is twice the length as the other three sides.
- If the length of the base of the tile is one unit, then the length of the middle triangle’s three sides are 3 units, 4 units and 5 units. The layers of the tiles within the trapezoids are also 3, 4, and 5.
- Small trapezium is made out of 9 smaller trapeziums. Bottom trapezium is made out of 16 smaller trapeziums. Larger trapezium is made out of 25 smaller trapeziums.
- The number of tiles on each side of the triangle follows Pythagoras Theorem: 3
^{2}+ 4^{2}= 5^{2}, which is 9 + 16 = 25. - The image includes an aspect of scale.
- The small pink polygons shapes make a negative internal outline of a right-angled scalene triangle.
- That the fewer pink polygons on each section related directly to the length of the sides of the internal outline of the triangle, that is, fewer pink polygons, shorter sides.
- I noticed that the depth and width of the outer shapes was linked, that is, left side shape is 3 pieces deep and 6 ‘lengths’ wide and consists of 9 pieces, bottom shape is 4 pieces deep and 8 ‘lengths’ wide and consists of 16 pieces and finally upper right shape is 5 pieces deep and 10 ‘lengths’ wide and consists of 25 pieces.

**I wonder …**

- Is the angle exactly 90 degrees?
- How many trapeziums there are?
- How long did it take to make?
- Why are there two different colours?
- How many blocks would it take to fill the right-angled triangle?
- Are sides ‘a’ and ‘b’ equal to ‘c’ in length?
- If the bottom section would fill the triangle perfectly?
- Are the small trapeziums arranged in a particular way for a reason? Or is it random to fit the desired shape?
- Do the larger shapes go down in size proportionally and is there a specific number to make up each shape?
- Would the area of the trapeziums be bigger or smaller than the area of the triangle in the middle?
- What the two remaining internal angles would be (excluding the right-angle).
- Why using trapezoids to represent Pythagoras Theorem also works? Is it because the ratio of the area of the trapezoid to the square is fixed?
- I wonder if the sizes of the trapezium differed, what the effect would be on the right-angled triangle on the middle? Is it possible to make an isosceles or equilateral triangle in the centre?
- How many triangles can each Isosceles Trapezoid be split into?
- How many other shapes are present in the Isosceles Trapezoids? For example – I have already noticed that triangles can be found — what other shapes are there?
- What is the reasoning for this image? Why was it created?
- How I could start a conversation with the students regarding this shape and what they may come back with?

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Skyscrapers are one of my favourite logic puzzles. They are a Japanese creation, introduced at the first World Puzzle Championship^{1} in 1992.

Skyscrapers are a type of Latin Square puzzle. A Latin Square in an *n × n *grid filled with *n *different symbols, each occurring exactly once in each row and exactly once in each column. (Sudoku is another type of Latin Square puzzle).

In a Skyscraper puzzle the objective is to place a skyscraper in each square, with heights between 1 and *n*, so that no two skyscrapers in a row or column have the same height. The numbers (clues) on the outside of the grid tell us how many skyscrapers are visible from that position. (I like to imagine that I’m standing on that number and along the street that is the row/column.) Shorter skyscrapers aren’t visible behind taller ones.

We use logical deductions to solve the puzzle. For example, in the puzzle below, the clue ‘4’ tells us that the skyscrapers must appear in ascending height order in that row/column. Similarly, the clue ‘1’ tells us that the tallest skyscraper must be adjacent to the clue. That leads us to the partially-filled grid below. If you want to solve it yourself, the solution is at the bottom of this post. You can also play them online at Brain Bashers.

It is fairly easy to turn a skyscraper puzzle into a hands-on activity — just choose objects of different heights. Teachers often use linking cubes. You can also be more creative; at David Butler‘s One Hundred Factorial gathering at the University of Adelaide in May, we experimented with video cassettes (remember them?) and cups of different sizes.

A while back, I wanted to make several hands-on sets for 5 × 5 grids to use with groups of school students. They needed to be cheap, lightweight, compact and portable. So, I made paper cylinders that nestle inside each other. You can download and print the skyscraper cylinders. The tabs are meant to show where to overlap and tape. You can use them with these puzzles (print A3 size): Puzzle 1, Puzzle 2, Puzzle 3, Puzzle 4, Puzzle 5.

My plan for MATH 1070 was curtailed by our short week (Week 3). I had planned the activity with these goals:

- Form visibly random groups with four students so that students could meet a few more classmates.
- Work collaboratively towards a common goal (and contrast this with the competitive nature of Prime Climb last week.)
- Practice claims and warrants as part of the focus on Maths Disputes: ‘I think <claim: this number goes here> because <warrant: my reason>.’

There are a variety of reasons to use skyscrapers in the classroom; you might like to read these posts by teachers: Mary Bourassa, Mark Chubb, Sarah Carter. Any activity introduced into the classroom should be intentional. You might like to think about these dot points. Mark has a fuller list in his blog post.

- If giving these puzzles to individual students is different than to groups of students.
- If a physical model is different than a pen-and-paper version.
- If you’ll use it as part of a lesson or as a ‘time filler’.
- What you’ll do if students give up easily.

If you give them a go, let me know what you think!

[1] Source: www.gmpuzzles.com/blog/skyscrapers-rules-and-info

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This year, I wanted to turn this into a student-driven rather than teacher-led activity. I also wanted to create opportunities for even deeper mathematical exploration. In this post I’ll briefly outline how this unfolded.

A goal for this year is to do better at helping students be good mathematical colleagues. I’ve been making heavy use of Chapter 12 of Tracy Zager’s book to guide this endeavour. I also wanted to begin using visibly random groups to build our mathematical community. However, I’m mindful it can be confronting to work with complete strangers, so I had students pair up first with someone they knew. (Pairing students up was also to serve another purpose that will become apparent later.)

I randomised the pairs by handing out cards from another of Dan’s games, the delightful Tiny Polka Dots. I deliberately used cards with different representations of 1, 2, 7 and 9 (with 8 as a back-up). Pairs with a different representation of the same number formed a group, one at each table. I gave them the rest of the cards for their number, and we did a quick ‘Notice and Wonder’ on the different representations.

Rather than show students the Prime Climb hundreds chart arranged in columns of 10 (the image earlier in this post), I wanted to foster noticing and wondering by having them construct the charts *themselves* with mini-cards of the numbers: physically handling, examining, ordering and organising. The (roughly) six students at each table arranged the cards into charts with the number of columns corresponding to their Tiny Polka Dots card (with 1 and 2 corresponding to 11 and 12, respectively). Click on the images below to make them bigger. What do *you* notice? What do *you *wonder?

To add impetus to the discussion, I relayed that part of the weekly task (contributing towards their course grade) was to individually write a forum post with at least five things that they noticed and wondered about their charts. It was heartening to see students collaboratively generating lists of their many observations.

The final part of this activity was to have students play Prime Climb in a way that compels them to articulate their thinking. One observation from playing Prime Climb at One Hundred Factorial with David Butler was that playing in pairs had an initially unexpected benefit of making thinking visible. (Side note: Bodyscale Prime Climb—where the numbers are A4 sized and the player is the pawn—is the most wonderful way to experience this game. Walking the board gives a different perspective to the relationship between numbers. You also need at times to shout your thinking across the board to your partner, which really makes thinking visible! Read more in David’s blog post.) We used a modification of the rules devised by David. This is the printable version that I wrote based on the rules that come with the game.

Collaboration and competition reached ear-splitting levels, so much so that we were asked to quieten down from those in the classrooms around us. (I sheepishly and profusely apologised later.) This was definitely a good start to building community.

While the in-class activities concluded with playing Prime Climb, there is so much more exploration provided by the cards. David, and later I, explored the different patterns that emerge when the cards are arranged in different ways. Others chimed in on Twitter with ideas; click the links above or look at the images below for more. The Prime Climb colouring is such a rich medium!

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I have always loved maths, but the reasons why have changed dramatically over time.

This is my Year 1 work. It reminds me about what I thought it meant to be good at maths: lots of ticks on neat work, especially if it was done quickly.

This attitude was reinforced by my report cards in primary school. A typical one looks like this. Note the focus on speed and accuracy. I loved maths because I was good at it.

Our Year 2 classroom had a corner filled with self-directed puzzle-type problems. If students finished their work early, they could go to the puzzle corner. I recall spending a lot of time there (my report says I was put in an extension group). Looking back, I’m sad that not every student had the same opportunities to engage with these richer, stimulating problems.

Outside of school, I loved doing and making up puzzles. I looked for patterns everywhere. I was always thinking about different ways to count, to organise, and to get things done more quickly. Growing up on a rural property, I had a lot of chores and time to think. For example, I’d think about how many buckets of oranges I could pick in an hour, how long it would take us to fill an orange picking bin, the different ways I could climb the rungs of the ladder, and so on. But I didn’t connect these ideas to maths.

Most of my school maths memories involve doing exercise after exercise from the textbook, but that was fine by me because I could put a self-satisfied tick next to each neatly done problem (after checking the answer in the back of the book!). I remember one high-school maths project to work out the most efficient way to wrap a Kit Kat in foil. It stands out in my memory because it was so different to the rest of maths class.

There were gaps in my knowledge along the way that I tried to cover up. I missed a month of Year 4 due to illness, and a substantial chunk of that time was devoted to fractions. When I got to algebraic fractions in later years, I would furtively use my calculator on simple examples to see if I could work out the right ‘rule’. Now I congratulate myself on having the sense to work it out for myself by generalising from specific examples. In Year 12 I felt embarrassed for using straws and Blu Tack to make visualisations of 3D coordinate geometry; everyone else could do it in their heads. Now I’m proud that I found a tool to help me make sense of the maths.

In Year 12 I hit a big obstacle. All my grades went downhill, including in maths. My maths report card says that I was ‘prone to panic attacks when working against a time constraint’. I don’t remember that, although I do remember crying (which I almost never do) in my maths teacher’s office and thinking that I didn’t know anything. I realise now that much of my maths schooling was about memorisation but not about understanding, and that it had caught up with me by Year 12.

Despite my mostly mediocre grades (I got a D in physics!), I did okay and was offered several university places. My love of the English language drew me to careers such as law, journalism and psychology. But I had also applied for and been offered a place in mathematics. Despite this, I chose to repeat Year 12. I took maths again because I still enjoyed it. The second time around it seemed to make a lot more sense; my scores were 19 and 19.5 for Maths 1 and 2. At the end of Year 13 I was awarded one of the first UniSA Hypatia Scholarships for Mathematically Talented Women. This boosted my confidence and made University study more affordable for a country kid. So, I decided to do mathematics. I also enrolled in a computer science major because I wasn’t sure what kind of job you could get with a maths degree.

Most of my undergraduate mathematics experience was the same as high school. I got Distinctions or High Distinctions for all my subjects (except Statistics 3B where I scraped a pass). I did most of my thinking in my head and then committed it to paper. I produced beautiful notes, and would rewrite a page if it had a single mistake on it. On reflection, I had a fairly superficial understanding of mathematics, but knew what to do to get good marks. I got disenchanted in the third year of my four-year degree and briefly considered quitting, but I had never quit something so important so I kept going.

At the end of third year, I had an experience that made me sure I wanted to be a mathematician. I attended a Mathematics-in-Industry Study Group. This is a five-day event that draws together around 100 mathematicians. On the first day, we listen to five or six different companies tell us about a problem they have that needs solving. For example, they might say ‘we want to stop washing machines from walking across the floor when they are unbalanced’ or ‘we want to know the best way to pack apples in cartons’. The mathematicians then decide which problem they want to work on, and smaller groups spend the next three and a half days feverishly trying to find a solution.

It was transformative as I witnessed, first-hand, mathematics put into action. I also saw how mathematicians creatively and collaboratively approach solving problems. I watched accomplished mathematicians initially not know how to start. I saw them making mistakes. They had intense (but friendly) discussions about whether something was the right approach. It was a defining moment, because it showed me how mathematics is *really* done, beyond learning mathematics that’s already known, or applying algorithms without a sense of why we would do so. I saw the true habits of mathematicians in action. I also discovered the important role that communication plays in mathematics, and that I could put my love of the English language to good use.

The transition from doing maths exercises with answers that were ‘perfect’ the first time to the more authentic and messy problem-solving required for mathematical research was not an easy one for me. I found it difficult in my PhD to accept that I was not perfect and that I had to constantly draft and refine both my mathematical ideas and my writing, especially because I had never been taught these skills. But I was helped in being surrounded by more experienced mathematicians who modelled, if not explicitly articulated, that this was how mathematicians really work.

It’s eight years since I was awarded my PhD, and I can now say that I am quite comfortable with this ‘messy’ approach to maths. I like to say that mathematicians are chronically lost and confused, and that is how it is *supposed to be*. It would be ridiculous for mathematicians to spend their days solving problems that they already know how to solve. So, being uncertain about whether something will work, or uncertain about what to do next, is a natural way for mathematicians to be.

I started teaching mathematics during my PhD. At first I taught exactly as I had been taught, with procedures and algorithms. But I also didn’t want to respond to a student with ‘Because that’s the rule’, so I started trying to really understand why maths concepts worked the way they did. I learned so much more about maths when I started to explain it to others. The way I taught expanded to include visual ways to think about maths, a variety of representations and approaches, and other flexible ways of thinking. It wasn’t natural to me at first (and at times I still solve arithmetical problems in my head by imagining a pen writing the algorithm) but it has immeasurably enriched my own understanding of mathematical concepts.

I also realised that the way I was taught was not the way I wanted to teach, but I wasn’t sure how to change that. I sought ideas from the internet, and eventually stumbled into the early days of the online community that is the MTBoS (the Math Twitter Blogosphere), although I didn’t realise that until much later. I lurked for a long time because I felt like an outsider: I wasn’t a school teacher (what did I know about education?!) and I wasn’t located in North America. Today I couldn’t imagine teaching without the support of my professional community on Twitter which extends all around the world.

Around five years ago I decided that I could help break the cycle of traditional procedural-based teaching by supporting students, particularly preservice teachers, in experiencing maths in the ways that I and other professional mathematicians do. So, I designed a course that gives students these problem-solving experiences alongside learning skills for thinking and working mathematically. I hold these word clouds from Tracy Zager in my head as a reminder and a motivation of what I am trying to accomplish. (You can read more about how I found them here.)

I still love ‘cracking puzzles’ in maths like I did in Year 2, but my love of maths has expanded to include learning how others think about mathematical ideas. In almost every class I see a student think about a problem in a way I’d never imagined, and I love it. Listening to student thinking is why I’ll never tire of teaching, and it helps me to be a better teacher. I can’t wait to learn from you.

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In case you are not familiar with it, the ‘Notice and Wonder’ prompt involves asking two questions: ‘What do you notice?’ and ‘What do you wonder?’. These are powerful questions to engage students. ‘Notice and Wonder’ helps lower the barrier to entry for all students and encourages sense making.

Notice and Wonder is definitely one of the top five actions that have transformed my teaching. Like Kate, I love how expansive and inclusive these two simple prompts are.

Me too. #NoticeWonder has been transformative in both my teaching and thinking.

— Amie Albrecht (@nomad_penguin) May 26, 2017

In previous posts, I’ve focused on using Notice and Wonder in problem-solving contexts like Conway’s Rational Tangles or a paper-folding investigation, intriguing prompts like the Prime Climb Hundreds Chart or in the world around us, and as a sense-making activity.

In this post I want to quickly share two recent experiences I’ve had that connect ‘Notice and Wonder’ with the types of concepts or questions that we encounter everyday in our classes, rather than more occasional problem-solving puzzlers.

In today’s lecture we were revising in preparation for the final exam. My focus was on helping students work out how to get started on questions when they don’t know what to do. On the spur of the moment, I started this question by asking what they noticed.

We noticed:

- The terms go negative, positive, negative, … .
- The denominators are multiplied by 3 each time.
- The numerators go up by 1 each time.
- There are five terms.
- The question has the sigma symbol in it.
- It says it’s a series, which we did in the context of sequences and series.

I asked if we could use these ‘noticings’ to write down one general term that could be used to describe any term in the series. And we were off! The alternating signs caused some consternation, and a wondering about how we could make that happen when the sum would ‘add everything up’. That was fun to tackle. There was another wondering about whether we were required to give a final numerical answer, which focused our attention on the word ‘express’.

What was particularly powerful was having a checklist of features from our ‘noticing’ work that we needed to be sure we incorporated in our final ‘sigma notation’ expression of the series.

A few weeks ago I was preparing for a lecture that introduced graphs of quadratic functions for the first time. At the last minute, I decided to show this graph and prompt for Notice and Wonder.

We noticed:

- The graph has two
*x*-intercepts, one positive and one negative. - The graph has one
*y*-intercept which is positive. - There is a maximum value at (2,9).
- The curve is in all four quadrants.
- The shape is ‘downwards’.
- (They probably noticed more features.)

We then went back through this list and expanded it into things we wondered:

- Could we have two positive or two negative
*x-*intercepts? What would that look like? (We sketched or talked about some possibilities.)

Instead of two*x*-intercepts, could we have one or even none? (We sketched some possibilities.) - We asked similar questions about the y-intercept.
- I introduced the term ‘vertex’ for the maximum. We wondered what other possibilities there are, and talked about the vertex being a minimum.
- We wondered whether the curve could be in exactly one quadrant? Or two quadrants? Or three quadrants? (I was not expecting this!)
- What other possibilities are there for the shape? I introduced the terms ‘concave up’ and ‘concave down’. We drew a concave up quadratic. We connected these to whether the vertex was a maximum or a minimum. We wondered about putting the shape ‘sideways’, but then discovered that it wouldn’t be a function.

This was a pretty strong start to the lecture as it previewed everything I planned to introduce in the next 90 minutes. I then took it one step further and showed three different forms of the equation of the quadratic. In the spirit of full disclosure, in my haste before class I made a mistake with two of the signs. When we discovered this, there was a nice ‘sense-making’ diversion as we expanded/factored the RHS of each equation. Establishing that these were alternative, equivalent forms of the same function turned out to be useful later too. Below I am showing the corrected versions.

Now we worked on connecting the different representations with the features that we had just noticed.

- From the standard form, we could ‘see’ the
*y-*intercept. - From the factored form, we could see that the factors related somehow to the
*x*-intercepts. - From the third form, we could see that the terms related somehow to the vertex. We then named it ‘vertex form’.
- We also discussed the negative sign in front of the
*x*^{2}and how that related to the shape. I don’t think we discussed it in class, but I can see now how we could develop that idea from the vertex form and the observation that, for any value of*x,*the*y*value will be less than or equal to 9.

This short introductory discussion motivated the rest of the lecture in such a way that some of the later material didn’t need to be discussed in the depth that is usually required. I’ve created more time within this topic!

I constantly marvel at how these two simple questions — asked together or independently — have such a positive impact on the learning that happens with my students and for me.

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One of the activities I chose for this year was Conway’s Rational Tangles. I’ve previously written detailed notes about running the activity with pre- and in-service teachers. For the Maths Experience, apart from the inherent fun of ‘playing’ with ropes, I wanted students to have a collaborative and authentic problem-solving experience. I introduced the activity as one that mirrors mathematical research — full of questions, puzzling moments, uncertainty, frustration and hopefully also joy. I emphasised that we might not solve the problem, but that the experience of working mathematically was our goal, which includes making wild conjectures and having out-of-the-box ideas!

In this post I want to highlight one addition I made to the activity described in my earlier blog post — the inclusion of the ‘Notice and Wonder’ prompt^{1}.

I started the session by showing students the short video below, edited from one I found on Youtube by Tom Hildebrand. Specifically, I turned off the sound, cut out the whiteboard, and sped it up significantly. Then I asked the two magic questions: ‘What do you notice? What do you wonder?’ Take 70 seconds to watch the video, and see what you think.

Here is what they **noticed**.

**Group A**

- They are trying to untangle the ropes.
- One person hangs on to one end of the rope for the whole time.
- They rotate 90 degrees clockwise.
- There is a plastic bag.
- Twist involves exactly two people and occurs in exactly the same position.
- They untangle using exactly the same types of moves they used to tangle.

**Group B**

- Four people holding two ropes.
- Same person holding the same end for the whole activity.
- When rotating, one person moves clockwise. (Later refined to each person moves one position clockwise.)
- The twist movement always involves the two people on the right. The same position goes under each time.
- There was some pattern they kept repeating.
- They did some moves to get a knot. Then they did some more moves and there was no knot.
- There was a bag.
- There were four rotations before the bag appeared and eight rotations after.
- Sometimes there is a different number of twists after a rotate.
- A twist after a rotate goes ‘perpendicular’. (Not sure what that means!)

And here is what they **wondered**.

**Group A**

- What’s the deal with the plastic bag?
- What’s the deal with the teacher?
- How did they decide when to stop tangling and start untangling?
- How tangled was the rope?
- What did the teacher and the student pass to each other? (Scissors.)
- How did they work out how to untangle? (I explicitly prompted this question — although I’m sure they were all thinking it.)

**Group B**

- How did they know how to untangle the ropes? Was it from memory?
- What is the point of rotate? It doesn’t seem to change the rope.
- Does the bag have something to do with the tangling?
- Is it a proper knot? Or just a tangle?
- What is the teacher doing?

There was more conversation that I didn’t manage to capture. (Next time I’ll record it!) Group A spent around 10 minutes on Noticing and Wondering. Group B spent 15-20 minutes. We then largely ran the session as I’ve detailed in the earlier blog post.

What effect do I think Notice and Wonder had? I noticed that students were keen to try the problem for themselves. They made sense of the situation, became intrigued and engaged, and then made the problem ‘theirs’. As a group, students saw that others had interesting ideas. They added on to each other’s thinking. I suspect that it also smoothed the way for working together more intensely once we broke into smaller groups where students didn’t necessarily know one another. It also became more natural for them to Notice and Wonder as the session progressed. All in all, it’s a great modification to a thoroughly engaging activity.

[1] I trialled this with teachers at the MASA conference in April.

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Well, it turns out that many of us want to read about lessons that are either uninspiring or failures. We want to know that there are others who have the same experiences that we do. That not every class is sunshine and lollipops.

Yesterday, Annie Perkins tweeted the following.

Hey #mtbos, had good convo w/ @PettisChristy which brought up good Q: are any bloggers writing about their lesson fails? We should be.

— Annie Perkins (@Anniekperkins) May 7, 2017

It led to the hashtag #lessonfail (my suggestion of #lessonmeh was far less popular ) and a huge influx of tweets of people sharing their own less-than-perfect teaching moments. Because we are all imperfect humans who make mistakes. Often. And we are constantly learning how to be better.

If you are like me, you view your students’ mistakes as learning opportunities, not learning failures. We need to permit ourselves the same freedom to fail, to learn, and to grow. And we need to talk about it with each other, from beginning teachers to those who have been in the game for a long time. I shared two of mine here. Thanks to those who has shared theirs in the last day or two: Annie F, Annie P, Bryan, Christine, David, Ilona, Madison, Tracy, and those that I missed. And if you aren’t ready to share, I understand that too. It’s hard to expose our vulnerabilities to others, for whatever the reason. Thank you to everyone for warmly responding to those who share. We are stronger together.

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The busier I get, the less I seem to read for pleasure. To redress this, my plan is to read 50 books in 2016. Fiction, mathematics, Australian politics, biographies, non-fiction, anything. Some books are short novellas which you might think of as ‘cheating’. Whatever. Despite the fact that I am counting, the number doesn’t count. It’s just a target to get me to read more.

I am tweeting 140 character reviews with #read2016, but I’ll also post the books here in three parts, one every four months. The maths ones (*) might be the subject of separate posts.

There were 19 books in Part 1 (January – April), 16 books in Part 2 (May – August) and 18 books in Part 3 (September – December). That makes 53 books in 2016.

*Black Rock White City, A.S. Patric.*It took me ~50 pages to warm to the story, but then it was unputdownable. A decidedly worthy winner of 2016 Miles Franklin Award.#read2016: A couple almost unknowingly clinging to each other through deep wordless grief, and yet a hopeful book.

*Commonwealth, Ann Patchett.*Wonderful writing. Skilled in capturing moments and innermost thoughts in few words. As a promising relationship between a famous author and a waitress begins: ‘He patted the top of her hand, which she had left close by on the bar in case he needed it.’ A glimpse of a left-behind, overworked mother of four young children: ‘The speed at which their mother ran from work to school to the grocery store to home had doubled. She was always arriving, always leaving, never there.’#read2016: Vignettes spanning 50 years woven together to tell the story of complex blended family relationships.

- Postcards from Surfers
*, Helen Garner.*Eleven short stories in true Garner style.#read2016: Stories that never use more words than they need. Expertly constructed.

*Dying: A Memoir*,*Cory Taylor.*I first learned of Cory Taylor on the fabulous ABC ‘Terminally Ill’ program of the ‘You Can’t Ask That‘ series. Cory was frank — the same as in her memoir.

#read2016: Clear-eyed. Unsentimental. A deeply reflective view of dying and of life. Moving.*Notes on An Exodus,**Richard Flanagan.*Richard Flanagan won the Man Booker Prize for his remarkable ‘The Narrow Road to the Deep North’. His ‘notes’, along with sketches by Ben Quilty (Archibald Prize winner), paint powerful portraits of Syrian refugees in Lebanon, Greece and Serbia.#read2016 (1): Devastatingly moving portraits of Syrian refugees from two of Australia’s most acclaimed in their crafts.

#read2016 (2): A slim volume but not at all light. Honours their dignity + courage. ‘Refugees are not like you and me. They are you and me.’*The Good, the Bad and the Unlikely: Australia’s Prime Ministers*,*Mungo MacCallum.*More than 29 biographies, this also brings together the story of Australian politics.

#read2016 (1): A lively and humanising view of each of Australia’s 29 PMs. Witty + concise writing that had me laughing (or snorting!) out loud.

#read2016 (2): I learned many things, but am still struck by the news that we had a PM with the middle name of ‘Christmas’.*The Curious Story of Malcolm Turnbull, the Incredible Shrinking Man in the Top Hat*,*Andrew Street.*I preferred the first book, ‘The Short and Excruciatingly Embarrassing Reign of Captain Abbott’, but only because Abbott was so laughably hopeless. The sequel certainly reveals some of the ineptitude of Turnbull.

#read2016: Grab the popcorn and dig into the spectacle. (If you don’t laugh, you’ll cry.) Street dishes out snark in spades.*Salt Creek*,*Lucy Treloar.*An interesting blend of fact and fiction.

#read2016 (1): Set on the South Australian Coorong in the 1850s as white settlers first encroach on the lands of the Ngarrindjeri people.

#read2016 (2): A beautifully-told, heartbreaking shameful story that matches historical truths. Starts painfully slow; gripping past pg 90.*The Long Green Shore*,*John Hepworth.*#read2016: Published 50yrs after writing of Australians in PNG during WWII. Banality alongside barbarity. Matter-of-fact yet almost poetic.

*The Hate Race*,*Maxine Beneba Clarke.*An Australian of Afro-Caribbean descent, Maxine Beneba Clarke tells what it is like to grow up as a person of colour in Australia.

#read2016: Packs a powerful punch, right to the stomach. A difficult, but important read. Particularly now.- *
*Which One Doesn’t Belong? Teacher’s Guide*,*Christopher Danielson.*The premise of ‘Which One Doesn’t Belong?’ is to consider four shapes, and ask the question. In the children’s picture book and its companion teacher’s guide, Danielson focuses on geometry and uses WODB to draw out rich mathematical ideas. The teacher’s guide provides convincing rationale and practical advice. There are plenty more WODB out there; try www.wodb.ca and the hashtag #wodb.#read2016: A delightful way to discuss + explore maths. The writing is crisp, purposeful, insightful + welcoming. A must-have for tchrs.

*Girt: The Unauthorised History of Australia,**David Hunt.*Australian history like it should have been taught at school. The ABC Radio podcast Rum, Rebels & Ratbags with Dom Knight is also worth a listen.

#read2016: Peppered with witticisms and dripping in places with sarcasm, this is a lively telling of Australian history like no other.- *
*Becoming the Math Teacher You Wish You’d Had: Ideas and Strategies from Vibrant Classrooms*,*Tracy Johnston Zager.*I have been madly awaiting this book for at least a year. It was so good I read it cover-to-cover almost as quickly as I could. It’s a beautiful, important book. Truly something special for all maths teachers. My full review is in this blog post.

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*Avoid Hard Work!*,*Maria Droujkova, James Tanton, Yelena McManaman.*There is a lot to like about this book, but ultimately I found it too light. I also have problems with the title.#read2016: A gentle approach to encourage mathematical problem solving with very young children.

*All That I Am*,*Anna Funder.*#read2016: A fictionalised biography of political activism against the Nazis in WWII. Crushing. Beautifully written. A page turner.

*Our Souls at Night*,*Kent Haruf.*The*‘Addie Moore and Louis Waters have been neighbours for years. Now they both live alone, their houses empty of family, their quiet nights solitary. Then one evening Addie pays Louis a visit.’*#read2016: A tender, quiet and impossibly beautiful tale of growing old together with grace.

*Victoria: The Queen*,*Julia Baird.*Loved the narrative-style approach, particularly once I realised it was built around impeccable research.#read2016: A hefty portrait of a formidable + intriguing queen. Flowing, engaging, well researched. Fascinating details of V as a woman.

*Monkey Grip**, Helen Garner.*Her acclaimed first novel. Reads like diary entries, with Garner’s perceptive view.

#read2016: Explores addiction, to hard drugs + to love. Written in the 70s; curious to see where Garner started. Still wondering if I liked.

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Tracy Zager’s new book ‘Becoming the Math Teacher You Wish You’d Had‘ is out, and it’s a treat. The central tenet of this important book is to ‘close the gap’ by making maths class more like mathematics, orienting our students towards the habits of mind of professional mathematicians. ‘Good teaching starts with us’ and Tracy companionably guides us through ten practices of mathematicians: taking risks, making mistakes, being precise, rising to a challenge, asking questions, connecting ideas, using intuition, reasoning, proving, working together and alone.

Tracy skillfully blends academic research, illuminating classroom dialogues, the thoughts of mathematicians and maths educators, and her own perceptive observations. This seamless mix is a real strength of the book; we not only see what habits are important and why, but how they can be enacted through specific teaching strategies, and the powerful effects they have on our students’ development as confident and capable mathematicians. The reader can’t help but be inspired by the teachers that Tracy holds up as exemplars of good practice. These teachers have so much respect for each of their students as serious mathematical thinkers. I was struck by the extent to which they would go to adapt instruction in response to student ideas and to support them in pursuing their own line of enquiry.

Tracy warns early on that the book is long—and it may be—but it is also captivating! The organisation is immensely practical; each chapter can be used as a self-contained guide for a particular mathematical habit. I can see myself repeatedly delving back into specific habits as the teaching year progresses. I read it cover-to-cover over a couple of days while curled up in a secluded cabin, pausing occasionally to stare out into the Australian bush and ponder what I can change in my own teaching. Some of my highlighted passages:

- From Chapter 3, Mathematicians Take Risks: ‘
*When we assign problems that have a single, closed path from start to finish, we’ve eliminated the possibility that students will take mathematical risks.*(pg 49)**There’s nothing to try if everything is prescribed.**‘*.*In my skills-based courses, I too infrequently give students opportunities to try and be successful with their own approaches. That’s something to work on. - From Chapter 4, Mathematicians Make Mistakes: ‘
*If we want students to learn from mistakes, we need to teach them how.’*(pg 57).*‘*How can I help students gain the skills to diagnose and learn from their mistakes, by themselves?**to teach students to make the most of the knowledge and experience they gained by figuring out their mistake**‘. - From Chapter 5, Mathematicians Are Precise: ‘
(pg 80). In my problem-solving course, I deliberately swung the pendulum from the typical procedure-based courses my students had mostly experienced towards creative, collaborative problem-solving. But I also need to find the middleground, where I place as much emphasis on rigour as I do on inquiry.**Math without inquiry is lifeless, but math without rigor is aimless.**There is no tension between teaching students how to solve problems accurately and efficiently and teaching students how to formulate conjectures, critique reasoning, develop mathematical arguments, use multiple representations, think flexibly, and focus on conceptual understanding.’ - From Chapter 12, Mathematicians Work Together and Alone: ‘
*If a major part of doing mathematics involves interacting with other mathematicians, then a major part of teaching students mathematics must be to teach students how, why, and whether to interact with one another mathematically.**Students need to learn how to ask for what they need from each other and to be what they need for each other**…***we need to teach students how to be good colleagues**…*it’s important we honor individual thinking and working time.**It’s not reasonable to expect students to collaborate at every moment, and that’s not how mathematicians work.’*(pg 312). This past semester, a few students in my problem-solving course commented that they needed more opportunities to work alone first, and more strategies to work effectively with group members. I’ll definitely be digging further into this chapter next year.

And, these phrases are going straight into my repertoire:

*‘Do you have more questions after doing this? What are you wondering about now?*(pg 149).*‘What does ______ have to do with _____?’*(Debbie Nicols, pg 191).*‘Remember that it’s hard to find mistakes when you assume that you’re right. So go back into it assuming something went wrong.’*(Jennifer Clerkin Muhammad, pg 284).*‘Would you recommend that strategy to someone you like?’*(pg 118).

There is so much to love about this book. The writing is both encouraging and empowering. It’s labelled K-8 but Tracy offers important insights to help teachers across *all* year levels; I have been nodding furiously and making notes throughout. This particular passage had me shouting ‘yes!’:

*‘We need to give ourselves permission to say, publicly, and with delight, “I never thought about it that way before!” whether it refers to addition, fractions, or place value. It is long past time for us to respect the beauty, power, and importance of elementary mathematics, instead of having contempt for “the basics.”’ (pg 208)*

Listening carefully to student thinking,* especially about ideas I thought I understood, *always gives me new insight. It’s why I’ll never tire of teaching.

I can confidently say that, alongside ‘Thinking Mathematically‘ (Mason, Burton and Stacey, 1982; 2010), Tracy’s book will become a cornerstone for my teaching. It is a gift to all maths teachers. But don’t just take my word for it; you can preview the book in its entirety here. The companion website promises more, and I can’t wait to look around!

**Update (22 December 2016):** The companion website is now live, and it is packed full of goodies. Be sure to check out the free study guide under ‘Getting Started’, which works for either an individual or group book study.

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*Edited to fix the confusion between × (multiply) and x (the letter).*

I have been *itching *to try Conway’s Rational Tangles with a group of students. I first read about this problem a couple of years ago in Fawn Nguyen’s excellent post. It looked super interesting, but I was still somewhat confused with how it works (not to mention *why* it works). So I was excited to be in Fawn’s ‘Conway Tangles’* *Math Micro-Session at the NCTM Annual Meeting in San Francisco this year, where it started to make some more sense.

This week I tried the activity with my #math1070 students. I waited until the last week of the course because: (1) now that we know each other better, I thought they’d tolerate me muddling through it, (2) their resilience and problem-solving skills for more challenging and ill-stated problems have increased. (Note that the ‘ill-stated’ part is my fault, not that of the problem!) I was upfront with them about how I was both excited and nervous about the session. It was a bit sketchy with the first group of students, but I was able to make some adjustments with the second group.

Below is a mash up of how I did it this week and how I would improve it in the future. This outline is based on Fawn’s write up, but I also pulled in ideas from Tom Davis’ thorough notes for a Maths Teacher Circle, along with the three-part outline from nrich maths: Twisting and Turning, More Twisting and Turning, All Tangled Up. We spent ~1.5 hours on the activity. Perhaps half of that was outside, with students doing it themselves.

Have four volunteers come to the front. Each person holds the end of a rope so that the two ropes are horizontally parallel. This is the starting position. This state has a value of 0.

There are only two moves that can be made: TWIST (T) and ROTATE (R).

A **TWIST** is when the person at the bottom left moves under the orange rope to the top left, as shown below. This new state has a value of 1. We notate this as . I tell the students that every time a TWIST operation is performed, the value of the ropes increases by 1. So, TWIST is +1.

A **ROTATE** is when every person moves clockwise to the next position, as shown below. (Note that this is from the starting position.) I say that I am not going to tell them the value of this new state. I’m also not going to tell them what ROTATE does; that’s for them to figure out.

Our aim is to (in my words) ‘tangle the crap out of the ropes’ by performing any number of **TWISTS** and **ROTATES **and then work out how to untangle the ropes back to horizontally parallel (with value 0). But, remember that there are only two available moves: TWIST and ROTATE. ‘Untwist’ and ‘Unrotate’ are not possible moves. (I wrote ‘aim’ because this isn’t the only goal, but it’s the one that students will initially want to work towards.)

At present, we have two questions:

(1) What does ROTATE do?

(2) How to get out of any tangle?

Before I let them loose with some ropes, we try a few more systematic experiments.

We reset the ropes to 0, and try **ROTATE **followed by** ROTATE** (RR). We discover that the ropes end up horizontally parallel again. That is, . We decide not to ever do RR unless we want to waste energy. We test this further by resetting the ropes to 0, and trying **TWIST** followed by **RR**. As expected, we end at a state with value of 1. We summarise:

The other possibility after an initial rotate is to try a twist. So we reset the ropes to 0, and try **ROTATE** followed by **TWIST** (RT). This action is kind of strange; the ropes stay vertically parallel no matter how many twists we do:

There are already some interesting conclusions that we could come to as a group, but I decide (based on experience) that it might make more sense if everyone is participating instead of watching.

Students get into groups of at least five: four on the ropes and at least one person recording the steps. I distribute the ropes ($1 each at Kmart; bargain!). We go outside. Maths classes in university are *never* held outside, so this is novel for all of us.

I suggest that to help answer Question 1 (What does ROTATE do?) we might want to break Question 2 down into further sub-questions.

(1) What does ROTATE do?

(2a) Work out how to get out of one TWIST; two TWISTS; three TWISTS; four TWISTS; any number of TWISTS.

(2b) Work out how to get out of a mixed up sequence, like TTRTTTRT, shown below.

Everyone starts with (2a), and works it out fairly quickly (15 minutes?). Their strategy to untangle is to always start with a ROTATE (otherwise we would be further tangling the rope), then to look at the ropes and ‘see’ what to do next. Eventually they write down how to get out of these positive integer states (T, TT, TTT, TTTT, …) and see a pattern. Try it for yourself! (Or look on page 5 of Tom Davis’ notes.)

In general, my students find it hard to conjecture what ROTATE does. I talk to each individual group in turn. To get them started, I write down something they’ve just done: . We can work backwards from T to realise that a=-1. We also realise that when we start with just twists, the value of the state keeps increasing from 0.** OBSERVATION: To return back to 0, ROTATE must involve a negative somehow.**

I suggest perhaps ROTATE is ×(-1). We look at . This works!

We test it on one TWIST: . This also works.

We predict what should happen with two TWISTS: . To get this untangled, we should be able to do TT. We try it with the ropes. Groan as it doesn’t work. (Note that some students have already forgotten that they know how to get out of two twists, from (2a).)

There is more conjecturing about ROTATE. For example, some students try ROTATE is -2. Later in the class discussion we realise that ROTATE can’t involve just adding or subtracting as RR would take us further away from 0 (positive or negative), and we know that . **OBSERVATION: ROTATE ****must involve multiplication or division (or perhaps some other operation).**

Most are still stuck. I ask them if they’ve done (2b) and untangled TTRTTTRT. If so, I tell them that the tangled state has value 3/5. **OBSERVATION: ROTATE must involve a negative and fractions somehow.** Some more cautious conjecturing eventuates.

If they are still stuck, I tell them that TTRTTR has value -2/3.

After working on it for ~45 minutes, some of them give up and demand the answer. I know there is more problem-solving work to come so I tell those that haven’t worked it out that ROTATE is ×(-1/a), where a is the previous state value. To summarise:

I ask them to come up with a scheme to efficiently get out of any tangle. (Later we decide that we aren’t sure that it is the minimum number of moves, but it seems efficient.) It works a bit like this: Get as close to zero with a numerator of 1 and a positive denominator (like 1/*m*) then ROTATE. This leaves you with a negative integer, –*m*, and you can TWIST your way *m* times back to 0.

Back in the classroom as one group, we summarise what we discovered, and make a few more observations.

- We go back and think about starting with a single ROTATE. Now that we know what ROTATE does, we see that the state becomes -1/0. This is like infinity. Another ROTATE brings it back to 0. When we start with a single ROTATE, TWIST leaves it exactly the same: . So we can have a tangle value of infinity. This is all kind of cool.
- We wonder if every rational number can be reached through tangles, and then be untangled.
- We wonder about how to prove the minimum number of moves to get out of each tangle.
- We talk briefly about function notation: and . We confirm that , so two RR leave the state unchanged. We talk about composition of functions, and how RTT is represented by

We talk about how this activity is suitable for a range of students and different areas of focus:

- problem solving and team work just by trying to untangle a tangle (no investigation into TWIST and ROTATE)
- practicing fluency with fractions
- older students can work with function notation and tackle some of the more challenging questions.

I reflect later how there is so much more depth in this activity than I had realised. I also realise that because it has so many different dimensions—physical manipulation, symbolic notation, numerical calculations, pattern recognition, conjecturing, teamwork, leadership—it gave students opportunities to shine in different ways.

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