Pick any number. We can make that number with four square numbers.

We've been carrying on our work investigating numbers. As we mentioned, Pierre Fermat had said that any number can be made by adding four square numbers.

We picked numbers and tried it out.

 We've made a big display of this in EC1:

Can you fill any of the gaps?

We'll give you any number with just four squares

Pierre Fermat, who lived in Toulouse, wrote in 1638 that any number can be made by any one of these ways:


1. Add three triangle numbers.

These are the triangle numbers:

2. Add four square numbers.

These are the square numbers

49   36   25   16   9   4   1   0

3. Add five pentagonal numbers.

 These are the pentagonal numbers:

 4. Add six hexagonal numbers.

These are the hexagonal numbers:

We had a go at the easiest one: making lots of numbers with four square numbers. We all picked a number, and then thought hard about which combination of squares would make it (Zero is a square number too.)

Number 16

16

I chose this number because: 

1. It is a square number… and I love square numbers!

1. Four squared equals 16. Four is my mum's favourite number, because she was born on January 4th.
2. I am eight years old, I like the number two, and if you multiply eight by two, you get 16.
3. This year, I will turn nine and my sister seven. 9+7=16