# Customer Review

Reviewed in the United States on February 23, 2018
Math is fun! Really, math IS actually fun, specially if you learn it from an early age. Books like this are the secret sauce to kickstart that sense of wonder and science and nature; and if you child manages to keep that healthy curiosity all the way up to the adult age, expect him to have a bright future (math is essential to land high-paying jobs in the tech industry, for example).

This lovely book by Danica and Jennifer is meant to teach your small child all the different ways to sum two numbers and get 10 as a result. After this book, your kid will know that 10 is sum of 2 and 8, of 3 and 7, and many other ways (how many?). This seems like an easy task, right? For us adults it is indeed, and for your kid it will be too after this book.

And if your child enjoys this book, there is lots more to explore after that. For example, tell your child there is a game based on this! It's called "Kakuro", and it plays just like the well-know Sudoku: you have to fill in numbers in a grid, but this time the number must sum to given value. If the value is "10" and there are two empty cells, then the answer will certainly be one of the combinations we have learned in the book, such as 3 and 7! (To find out which is right combination, you need to check the other clues, just like a crossword).

You may also be surprised to discover there are mathematicians who dedicate their life to study the very same problem posed in the book, of describing a number as a sum of other numbers. They call it "the partition problem". We have seen that 10=7+3, but if we allow more than two numbers, how many combinations there are? We can write 10=3+3+6, or 10=1+5+4, or my favorite 10=4+3+2+1. There are 42 different combinations! And, as it turns out, to this day no one know a formula to discover the number of partitions of a number, without calculating first the partitions of all number that comes before it.

We can find approximations though, one of them was found by the great genius from India, Srinivasa Ramanujan. Hollywood just made a movie about him, search for "The Man Who Knew Infinity". There is even a scene in movie with him explaining the partition numbers and calculating the approximation!

There are so many stories that you can tell your kid after this. Another example: see how math in this book is made with poetry? It even has rhymes!
Wouldn't it be fun if mathematicians used poetry and rhymes to express mathematics? Well, this used to be the way in the past! Certainly you must remember the quadratic equation (minus b, plus or minus the square root of delta, and so on). There is a formula for the cubic equation as well, and the person who created that formula, the italian mathematician Tartaglia, presented it to world in 1539 as a rhyming poem! Search in google for "Tartaglia's cubic poem", your kid will enjoy to know that!

Math is incredibly fun, and this book might be the one to unlock the potential in your child. Danica's text is great and Jennifer's illustrations are amazing (I must say my favorite character is caterpillar engineer). Don't pass it up!