Kids can spot mistakes in math books too

Read as if you edit

Previously, in one of my posts I wrote that I tend to read books as if I proof-read or edit them. There are a number of advantages in doing so. For example, reading books end to end ensures deeper understanding of the content. Attempting to solve each exercise in a book is also a positive thing to do, because even if you do not solve it, you can get a valuable insight just because you tried hard to solve an exercise. When you follow this advice, after a book or two this starts to happen automatically to you and you can’t help, but spot spelling mistakes, wrong diagrams used or mistakes in formulas etc.

To see a real example of the above suggestions let’s look at the All Things Being Equal book by John Mighton founder of the JUMP math teaching method. This book is not a math textbook, but a book about how math can be taught to kids. The main idea is that math can be taught to an average person and it doesn’t take a genius to like math and be productive in it. There are a number of exercises that John Mighton provides in the book to showcase his approach of teaching math at school. I’ve tried each one of them and lo and behold found a number of mistakes in the book. One mistake was spotted by my daughter. And this is exactly what I want to write about next.

Some concrete examples

I’ve got a softcover edition of the book, ISBN 9780735272903. On page 201 of this edition John Mighton provides an example of how a simplified Sudoku version can be accessible and enjoyable to kids. The regular Sudoku puzzle 9 by 9 cells looks as follows. Each row and column in the table below should contain all of the digits from 1 to 9, when no digit can appear more than once.

A simplified version is 4 by 4 cells, which is easier for kids to start to play with. Now, I’ll provide all four puzzles on the page 201 of the book.

Puzzle #1

This puzzle is solvable, so let’s move on to the next

Puzzle #2

This puzzle has a mistake in it. Try to find it yourself or jump to the end of the post for an answer.

Puzzle #3

It’s solvable. Move on.

Puzzle #4

This puzzle has a mistake in it and my daughter, who was in Grade 2 at the time, was able to spot the mistake.

Pay attention, that there cannot be a duplicate value on any row, column in the table.


When you spot and collect a certain amount of mistakes it’s good to inform an author of the book or a publisher about them. Usually, authors are grateful if you report mistakes to them and it could even result in a friendship or a nice communication with them.

It wasn’t the case with All Things Being Equal where there was no response when I sent the errata to the JUMP Math contact email. So I sent an email directly to the Vintage Canada who is the publisher of this book.

So take care and report mistakes, who knows where it will take you.

Answer to the Puzzle #2


2 thoughts on “Kids can spot mistakes in math books too

  1. The 4×4 sudokus are great for children. When I hosted a games club at Duc D’Anville Elementary, we replaced the numbers 1,2,3,4 with 4 different colors and used Lego pieces of these colors to populate the grid, ie no numbers used.

    The kids especially liked the from-scratch 4×4 color sudoku building when they realized they could create a partial one and then let a friend try to complete it, and vice versa.


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