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# Go Figure! A totally cool book about numbers

We recently decided to take a break from our "regular" math curriculum while we pursued a more topical approach to the subject and expanded the math notebooks we started last fall. This involved a trip to the library where we discovered this delightful gem by Johnny Ball. Go Figure! A totally cool book about numbers is perfect for notebooking AND for making math fun.

The book is divided into four sections. The first section, Where do numbers come from, covers the history of numbers, how counting began, and numbers from various ancient cultures. This section can be used to integrate mathematics with your history studies. Next is Magic numbers which is all about the patterns numbers can form and the tricks you can do with them. Here you will find things like magic squares, the golden ratio, big numbers, prime numbers, Pascal's triangle, and more. In addition to the basic facts and fun puzzles, there is a lot of interesting trivia to be learned here. The third section, Shaping up, covers geometry. And finally, The world of math shows various ways that math is hiding all around us.

My children and I really enjoyed working through the puzzles and activities included in this fun, colorful book. We learned a lot about math, and created some wonderful notebook pages. This book is definitely worth purchasing, as it is one you will want to refer back to over and over again.

## Prime Number Trivia

Some interesting facts about prime numbers that you can learn from this book:

* Prime numbers are pretty random, which makes them hard to find. Even when there appears to be a pattern, it doesn't continue. For instance, 31, 331, and 3331 are prime. But if you continue the pattern on for several more numbers, you will reach a number that isn't.

* Smaller Prime numbers can be found using a special tool known as a "sieve." (This concept was actually developed by a man named Eratosthenes. Although he is not discussed in this book, you may be interested in doing some additional research and completing The Sieve of Eratosthenes Notebook Page that I created.)

* You can cut any number of digits off the end of the number 73939133 and it will still be prime. It is the largest known prime number with this property.

* Multiplying prime numbers is easy, but splitting a number into its prime factors is more tricky. For really big numbers, it can be so difficult that huge numbers are often used as a "lock" for codes on the internet, with the key for this lock being the number's prime factors.

* The fact that the amount of years a periodical cicadas spends underground is a prime number (13 or 17 years), acts as a protection, because the time of their life-cycle can't be divided into smaller numbers and rarely coincides with parasites and preditors whose life-cycles are perhaps two or three years.

## Pascal's Triangle

Pascal's Triangle is one of the cool "math tools" you will learn about in this book.

* Chinese mathematicians were using "Pascal's" triangle at least 900 years ago.

* Pascal's triangle is full of fascinating number patterns.

* You can use Pascal's Triangle to count ways of combining things.

Pascal's Triangle Notebook Page

## Let Me Know You Were Here!

anonymous on August 25, 2011:

I bought this book when my son started first grade then loaned it someone before we ever got to use it. We never got it back and he's starting 6th grade now. We're currently using Life of Fred and loving every minute of it, but I'm thinking of adding this book back in after we finish LoF Decimals. i'm so glad you mentioned the other books, we may have to break between LoF books with those too!

Jimmie Quick from Memphis, TN, USA on February 15, 2011:

Love the two notebooking pages that go with the book. Fantastic!