Subtraction using a number square
Once the children are confident 'jumping' along a number line, they are introduced to using a number square to calculate addition and subtraction sums. This uses the same skills involved in using a number line (i.e. start with the bigger number and jump to the left), but it becomes increasingly difficult when crossing the tens boundary (i.e. subtracting from 51 to 49).
In this short video clip, Emily in Year 1 has been learning how to use her number square to subtract when crossing the 'tens boundary.'