Can your students recognise the same sum value in different forms? In this unit students learn that the answer on the left of the equals sign is the same as the answer on the right of the equals sign. For example; 67 + 44 is the same as 45 + 66. The first activity shows 8 sets of scales. Students need to add a number to the left hand side of the scale that equals the total on the right hand side. In activity two students complete 16 seesaws with subtraction sums.