Practise finding pairs of multiples of 5 that total 100. There are only about ten pairs and if possible they should be learnt.

What number do you need to add to make a total of 100? Probably the best way is to add on to the next whole ten and then count on in tens to 100.

You may have seen tables' grids: these are addition grids and work in just the same way, adding rather than multiplying.

Adding three numbers: stop watches at the ready to see how quickly these can be completed correctly.