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


Chasing New Horizons is the book you’ve never heard about

Have you ever heard about New Horizons spacecraft? Did you know that it flew by dwarf planet Pluto in 2015, which was never been done before? Did you know that in 2018 it visited a Kuiper Belt Object Ultima Thule, now officially known as Arrokoth? If you answered no to any of these questions and you are interested in deep space exploration then you may find this post interesting.

The post is a short review of the book Chasing New Horizons : inside the epic first mission to Pluto. If you already read other books on the subject, then this one could resemble to you The Interstellar Age by Jim Bell or The Right Kind of Crazy by Adam Steltzner. If not, then buckle up and lift off!

Back in 2015 Pluto was still a dwarf planet that little was known about except its orbit, its approximate mass and volume, and composition of its atmosphere. No space mission had visited it before, though one of the Voyager probes was planned to visit it, but it didn’t happen. In 2015 with a flyby of the New Horizons spacecraft, Pluto has revealed its secrets and new exciting data became available to scientists and a larger audience.

The book Chasing New Horizons is all about telling the story of how this flyby became a reality and how dedication and perseverance of a group of relentless planetary scientists, engineers and space enthusiasts put their careers on a line to make this happen. It was written by Dr. Alan Stern who was a Principal Investigator (PI) behind New Horizons mission and Dr. David Grinspoon, an astrobiologist, who also took part in the mission. It tells the story of how the mission was conceived back in late 80’s of the previous century, how it took about 27 years from an idea to its implementation and what obstacles the team had to overcome to make it a reality.

What I liked about the book

As I’ve already mentioned in my other post, I find the that the most interesting books are books written not by journalists, but by actual scientists, engineers, project managers and others, who were there, who made the decisions, who first hand experienced what happened before their own eyes.

This book stands out in comparison to similar ones about space, since it is able to engage readers in an exciting story of exploration of new horizons despite the hurdles emerging almost daily along the way, that would prevent other people from proceeding forward. I like how the NASA’s inner politics, engineering tradeoffs and solutions to emerging problems were described in detail in the book. This way a reader gets a better context of how the events unfolded and why.

Significant part of the books is also dedicated to describing day-to-day activities, such as mission planning, spacecraft housekeeping that were carried out to support the ongoing New Horizons journey to Pluto. By providing these details authors made it feel like you actually were there in mission control room observing what had happened in a real time.

All in all, books like this make you appreciate what we people are capable of when we are driven by high goals of exploration, knowledge advancement and pure joy of adventures. And such books make you crave for more.