Preschool Children's Knowledge of Addition and Subtraction

Two studies examine preschool children's knowledge of the effects of the physical processes of addition and subtraction on the relative amounts of two sets. Results indicate that children are very competent at these elementary problems though they often do not use numbers. They can select the set with more elements when the two initial sets are equivalent in number and operations are performed on one or both sets and when the initial sets are unequal but small in absolute size or very different in size. Most children recognize the inverse relationship of addition and subtraction.