Here we have a set of pages where the subtraction number sentence need to be completed. There are several different strategies which can be used to do this, depending on which number is missing. For example: in the number sentence 16 - ? = 7 the best way to do this is to count back 7 or to mentally subtract 7 from 16. But, in the number sentence ? - 9 = 7 the best way to find the missing number is to add 9 and 7. Thirdly the number sentence 16 - 9 = ? can be done by either counting back 9 from 16 or counting up from 9 to 16. Because there are different techniques within the one page some children may find this trickier than expected. Complete subtraction number sentences