Long before Catriona Agg’s *Geometry Puzzles in Felt Tip Pen* were all over Twitter, Ed Southall was doing something similar without felt tips. He and Vincent Pantaloni served up a smorgasbord of *Geometry Snacks* in 2017 and *More Geometry Snacks* the following year — but these are aimed at a (chronologically) grown-up market.

*Geometry Juniors*, as it says on the tin, is aimed at a younger audience. Or rather, it’s aimed at parents or carers of a younger audience; it’s as much for starting conversations about geometry as it is for direct instruction or to bamboozle puzzle-solvers.

Luckily, I have a seven-year-old who loves maths. The book says 8 and upwards, but Bill isn’t likely to let an inequality like THAT stand in his way.

From the get-go, *Geometry Juniors* is engaging and open-ended: many of the questions are of the “what do you notice?” or “can you…?” type, while others are significantly more leading.

This could be a double-edged sword: as long as both readers have a positive attitude towards maths, it will lead to rich and rewarding conversations; if either party isn’t in the mood for a maths chat, this is not going to be much fun for them.

Luckily, Bill is always in the mood for a maths chat. Here’s his take:

Something I want to say about

Bill Russ, age 7Geometry Juniorsis that it is great for young children (like me) to learn about simple steps in maths.This book has lots of interesting questions and facts. I also like the amazing illustrations of the pets, characters and resources. I’d like to thank the author of this wonderful book and the illustrator.

The progression of topics is clear and well-thought-out, each chapter building on the ones before it — starting with basics like “which one doesn’t belong?” and the properties of shapes, and ending up with tools that would start to crack the average Geometry Snack. The facts littered through the book are calculated to appeal to kids (“a *discorectangle*? But that’s ridiculous!”) My one quibble with the otherwise brilliant illustrations is that some of the 3D questions are ambiguous and give different answers depending on whether you assume no cubes are hidden behind others.

*Geometry Juniors* is colourful, cheerful and thought-provoking; I especially love the pictures of occasionally-confused students disagreeing and asking questions and generally modelling good mathematical behaviour, making it easy for the reader to step in and say “I think she’s right” or “I disagree because…”.

This is a book carefully designed to help mini-mathematicians develop their curiosity, reasoning and geometric knowledge. I think it will work best for grown-ups with a reasonable idea of geometry to begin with, but the curious will also get a good deal out of it.

### More information

Geometry Juniors, by Ed Southall, is published by The Mathematical Association and at time of writing costs £10.

Colin received a free copy of the book to review it.