Think carefully about how to work out an answer. 
Decide whether to use:

• a mental calculation;
• a mental calculation with some jottings;
• a written method;
• a calculator.

On the mental mathematics paper you are  allowed to write down information while the question is being asked.  On Paper 1 you are not allowed a calculator.  On Paper 2 you can use your calculator if you wish.

You should write down all of your working on both papers - even if you used a calculator!