MAKE THE ‘KILLER MATHS’ YOUR FRIEND
Here is a game you can play with your friends
Ask your friend to think of a number 1-10 and it has to be a whole number. (It doesn't have to be 1-10 it can be any number; it also works with decimals and negatives!) Tell them to multiply the number by 2. Tell them to add by an EVEN number like 10. Have them divide the sum by 2. Have them subtract by the original number they thought up. The answer should be half of the number that you told them to add if they did the math correctly.