You can add the number to itself to get a double. You can also multiply a number by 2 to get a double. When you double a number, it ends up twice as big. Here’s another example of how to use ten ...

Each small division between the centimetres is \( \frac{1}{2} \) centimetre. Now here is a metre stick. You can use it to measure longer lengths. 1 metre is written as 1m. There are 100cm in 1m.