11 October 2014

5 Maths Gems #9

Because I didn't write a gems post last weekend, imagine how much I have to tell you about today! Quick - let's get started...

1. Hula Hoops
Who needs technology when you can stick a hula hoop on the board? This simple idea, shared by @emziecampbell, is for teaching children to tell the time. It would work well for other circle-based topics too. Stick a hula hoop on the board and use it to teach circle theorems. Stick two or three on the board to make a Venn diagram. Hula hoops have novelty value, practical application and cost a mere £2.
2. Stuck Post-Its
Another simple yet effective idea, this time from @Misswrenmaths: 'stuck post-its'. Sometimes when students are completing practice questions in class, you end up repeating yourself numerous times as you move from student to student. Instead, put the questions on the board and ask students to stick a named post-it note on any questions they need help with - then they can carry on with the rest of the exercise without having to wait with their hand up. For example the picture below shows that you'd need to help one student individually with question 9, but it may be worth going through question 10 with the whole class, or gathering a group together to discuss it.

This technique stops duplication of effort and helps the teacher assess understanding, plus it has the benefit of getting students out of their seats, albeit briefly. Read the fascinating post 'A veteran teacher turned coach shadows 2 students for 2 days – a sobering lesson learned' from @grantwiggins and you'll see why this is important. A little bit of movement keeps students alert.

While I'm on the subject of post-it notes, I should mention a cool new app 'Post-it Plus' that was suggested by @dazmck. With this free app you can take a photo of a wall of post-it notes and then organise them digitally on your phone or tablet. Amazing.

3. Trig for Victory
@mr_g_walton demonstrated his brilliant creativity with his 'Maths Propaganda' posters.

Every poster is excellent so it was hard to choose three examples for this post!

In addition to the posters, Mr Walton suggests revision cards in the form of ration booklets and a school broadcast by the Ministry of Maths! Fantastic ideas. All 16 editable posters and associated resources can be downloaded here. Credit also to @El_Timbre for inspiring the 'Trig for Victory' poster.

4. Parabolic Multiplication
If you were at the recent Maths Conference in Kettering then you may have been interested in Johnny Ball's parabolic multiplication. This involves drawing a line from one point on the graph of y = x2 to another. Two examples are shown in the picture - the red line joins the numbers 3 and 4, crossing the y-axis at 12, an the green line joins the numbers 2 and 2, crossing the y-axis at 4. It's a bizarre multiplication method.

A full explanation is in this 'Cool Math Essay' from @jamestanton. The algebra is accessible and satisfying. Figuring it out would make a good task for bright GCSE students or sixth formers studying coordinate geometry.

If you happen to be visiting Germany then do go to the Mathematikum. There you will find a parabola drawn on a wall with a length of rope for visitors to tie from one point on the parabola to another - the point at which the rope crosses the y-axis is the product (source: qedcat.com). Does anyone want to take up the challenge of putting one of these interactive displays on their classroom wall? If so, please send me a photo!

5. Counting Circles
There's been a lot of buzz amongst American teachers on Twitter about counting circles. This is a simple and versatile activity to develop number sense and mental maths strategies. The original post #Countingcircles is by @wahedahbug.

Students take it in turns to count up (or down) in specified intervals. For example they could start at 35 and count up in 13s, or they could start at 12.1 and count up in 5.2s, or they could start at 3x + 5 and count up in 2x + 7s. See how creative you could be with this? You could use fractions, decimals, negatives, minutes, algebra...

Importantly, the teacher writes the numbers on the board as they are said. This makes the task accessible to all.
Meanwhile the teacher (an expert at multi-tasking) also pays attention to what the students are saying and any strategies they are using to find their answers.

Read the original post for the full background and lots of ideas. The writer says, "Counting circles in general seem on the surface like a routine that is just done 10 mins a day however it is much more than that. They help start a culture change in your classroom. They give students the opportunity to own math, to be successful in math, to “create” and share their strategies, to make mistakes and learn from them". The videos in this post are well worth watching before you try this out. Also, explore the hashtag #countingcircles on Twitter for inspiration.

Recommended Reading
At Parents Evening, I'm often asked the question 'How can my daughter stop losing marks to silly mistakes?'. I've never had a particularly good answer to this so @icecolbeveridge's post 'How can I avoid mistakes?' is really helpful.

Another article I enjoyed this week was 'Why Writers Should Learn Math' which was published in the New York Times in 2012. We all have to tackle bad 'mathitude' from students and adults alike. I agree with the writer when he says, "most people are so frightened of the name of mathematics that they are ready, quite unaffectedly, to exaggerate their own mathematical stupidity". 

What I've been up to
I’ve been busy. Because of their increasing popularity, I decided that Pret homeworks deserve their own website. It's only one week old but has already had a large number of visitors. Teachers have started to report back on their positive experiences of using these versatile homeworks. It's great to see an idea working well. Once students get used to them, they are an effective homework requiring minimal marking. Interestingly, other subjects (such as Science and English) have shown an interest in this format too.

Last week I also ran my first Twitter chat about transition to A level, on behalf of the NCETM. It's hard work hosting a Twitter chat - imagine dozens of good ideas being fired at you simultaneously! My related post 'Bridging the Gap to A level' featured in this week's edition of Academies Week (thanks to @oldandrewuk) - I subscribe to this paper so was very excited when it arrived in the post.

I also featured in the 'Behind the Mathematician' series from @WorkEdgeChaos - writing that post was a great opportunity for me to reflect on my teaching and think about what motivates me and what I find challenging.

I want to end today's post by encouraging you to book a ticket for @LaSalleEd's next National Maths Teacher Conference, which is on Saturday 14th March 2015 in Birmingham. Click here to book your free ticket - I'll see you there.


  1. The youtube channel Tipping Point Math posted a video last summer about parabolic multiplication: https://www.youtube.com/watch?v=eLR3zKxpcso&list=UUjwOWaOX-c-NeLnj_YGiNEg

  2. I love your blog! Chock full of great ideas, well and succintly described. Thank you!

    1. Thank you! Really nice of you to say. I'm so glad it's helpful. :)