Year 4 Multiple exchanges when adding Allowing children to try and explain what is happening is a crucial part of learning and we have just published an interesting addition problem which involves children trying to explain ‘multiple exchanges’. This happens in an addition question where the ones add up to ten and the tens add up to one hundred and the hundreds add up to one thousand – forming a sequence of multiple exchanges. If children can understand what is happening then it is a sure sign that they have a good grasp of addition. Go to Year 4 Addition