We’ve Got Your Number – a Royal Society Young People’s Book Prize shortlistee

We’ve Got Your Number written by Mukul Patel and illustrated by Supriya Sahai aims to show 10-14 year olds why almost everything in their lives boils down to maths, and explains why they should change how they get pocket money so they start with just 1p in the first week of the new year.

It’s bold and bright and full of cartoons. It covers everything from the maths of planets, space and time, to the way maths impacts on decisions you make every day, from what flavour ice-cream to have to how to choose a healthier snack. Brief biographies of mathematicians, such as Fibonacci, Euler and Al-Khwarizmi are interspersed with facts and lots of small projects to try out at home (with the solutions provided at the end of the book, so you can double check how you’ve got on).

With lots of short stand-alone sections, this book is easy to dip in and out of; this is just as well because it is so packed with information, it could easily feel slightly overwhelming if you tried to sit down and read it from cover to cover. I do wonder if this book will work better for us the longer we live with it, using it as a reference book to go back to when M, J and I want to explore a particular topic.

This book proudly believes its readers can understand quite complex mathematical issues; the unpatronizing approach continues in the resources list which includes several books and websites mostly marketed for adults, but which the author believes kids could also appreciate. If asked to recommend this book for a particular readership I’d suggest it’s not for the beginner/early mathematician, but rather for one who is already pretty curious about the way numbers work.

Although We’ve Got Your Number didn’t work brilliantly for us, it did prompt me to find some other ways to get M excited about maths. And so I turned to magic!

There’s a whole class of magic tricks based on maths, and many of them are easy to do, even if you don’t understand WHY they work. I taught M a Mind Reading Maths trick (below), which she then went on to perform in class in the “show and tell” slot one day. Cue lots of oohs and aahs, and quite a lot of street cred from her classmates and teachers. It definitely worked for boosting her confidence in and curiosity about maths. It looks rather long and wordy having typed it out below, but I do encourage you to give it a go. It’s simple, beautiful and packs a big punch!

Mind Reading Maths

1. Remove the tens, jacks, queens, kings and jokers from a complete deck of cards.

2. Shuffle the cards.

3. Ask your friend to pick any card from the deck. Your friend should not show the card to you, but they do need to memorise the number on their card.

4. Ask your friend to put her card down on the table, face down.

5. Now you (the magician), pick a card from the deck. Don’t show it to your friend, but do memorise the number on your card.

8. Lay your card face down on the table next to your friend’s card. It is important to place your card on the right hand side of your friend’s card as your friend sees it.

9. Give your friend a piece of paper and pencil to do a little bit of maths. Ask your friend to:
(a) Double the value of her card

(b) Add 2 to that number

(c) Multiply that answer by 5

10. Now you (the magician) need to to a little bit of maths. In your head subtract the number of your memorized card from 10.

11. Have your friend subtract your answer from her final answer.

12. Say “Are you thinking of this number?”. Flip over the two cards on the table, and the two cards together should make the number that your friend has calculated.


(If things go wrong, either you put your card on the wrong side of your friend’s card, or your friend got her maths wrong – you can always double check)

Click here to download a printable version of this trick!

Given how much fun we had with this one trick, I’ve now prepared some more Maths Magic Lunchbox Printables for M. I will put these in with her lunch this week so she can wow her friends with her amazing magic skills whilst they munch their sandwiches.

You can download my Maths Magic Lunchbox Printables here (sheet 1 – slightly easier maths), here (sheet 2 – slightly more complicated maths), and here (a blank sheet for friends to use as part of the magic tricks). I suspect the most popular trick will be the one you can use to work out the age and shoe size of your teachers and dinner ladies…

We didn’t have any music on whilst we learned our Maths Magic Trick, but if you want songs to go with We’ve Got Your Number you might enjoy these:

7 8 9 by Barenaked Ladies (totally child friendly, despite their name)

I Will Derive! (Inspired by I Will Survive. The maths in this is probably too difficult for most primary school kids, but adults will appreciate this song)

Math Math Baby (Inspired by Ice Ice Baby)

Here’s a whole Pinterest board dedicated to maths songs and videos.

Other activities which you might enjoy along side reading We’ve Got Your Number include:

Learning even more maths magic card tricks with Colm Mulcahy’s new book Mathematical Card Magic.

Play the lottery. Yes, just for this week, and only in the name of learning about maths, why not buy a family lottery ticket. You can work out your odds of winning using this helpful site (good for any lottery), which also provides a useful way to visualize your chance of winning, and some comparative odds so you can contextualise your chances.

Visit a maze (UK suggestions, US suggestions, Aus suggestions) and try to find your way out. If you’re stuck in a maze here’s a useful algorithm (a step-by-step method for performing a task) that will always eventually get you out of the maze: Keep one hand in contact with a wall as you walk. You WILL find the exit… but are you brave enough to try?

What’s your favourite number and why? What books have your found accessible, well pitched and exciting when it comes to getting your kids enthusiastic about maths?

Disclosure: I received a free review copy of We’ve Got Your Number from the Royal Society.

Each year the Royal Society awards a prize to the best book that communicates science to young people with the aim of inspiring young people to read about science. We’ve Got Your Number is on this year’s shortlist for the The Royal Society Young People’s Book Prize. The winner will be announced mid November.