When we double a number we add it to itself, or just multiply it by 2
This is also called finding twice the number.
Examples
Double 4 is
4 + 4 or 2 × 4 = 8
Twice 9 is
9 + 9 or 2 × 9 = 18
Lots of different ways of saying a calculation, but all meaning the same thing! Confusing, isn't it?
Don't worry - it will get easier the more you practise, so let's get started now!