Mrs Laird visited our class to show us a cool new mental maths game called ‘Back 2 Back’. As the title suggests two children stand back to back and write down a digit from 2 to 12. Neither player can see the other’s number.  The ‘caller’ shouts out what the sum of the two numbers is, from each player multiplied or added, and the players have to guess what each other’s numbers are by either subtracting or dividing their number from the sum.