How many times have you heard someone say 'I can't do mental arithmetic'?
Perhaps it is something that you have said yourself many times . . . I know I have!
The problem, I have found, is not 'I can't do mental arithmetic' but 'I don't know how to do mental arithmetic'.
This certainly was the case for me.
Let me show you what i mean.
If I were to ask you to multiply 43 x 11. Would you be able to do it? How long would it take you to do it?
If you asked me tha...