What is happening here?
When splitting numbers, your child learns that one number can be put together from two parts in many different ways: 7 = 3 + 4 = 5 + 2 = 6 + 1. A child who masters this will later calculate faster and more flexibly.
What helps at home
Use everyday objects: split 7 grapes onto two plates, in every possible way. Let your child find out for themselves how many ways there are.
Important: the goal is not to list all the splits as fast as possible, but to understand the idea. Ask "Is there another way?" and let the child search.
What can go wrong
With problems like "5 = _ + _", some children keep picking the same split they saw last. In that case, change the starting object or turn the problem around: "You already have 2, how many more do you need to reach 5?"