Blank part-part-whole bonds, four to nine per page, with the total filled in, or the total and one part, for totals of 10, 20 or 100.
A number bond is a total joined to the two parts that make it. Filling in the missing part builds fact families and shows addition and subtraction as the same relationship.
Start with the total and one part given, so the task is to find the other part, then move to total only and ask for as many different pairs as the child can find.