The Eggs Story: Sums of 3 Addends

Illustration of a chicken

In the egg story children are working with sums composed of three addends. At first orders for three different kinds of eggs come in with the sum unknown— the problem structure with which children are most comfortable. Next the egg orders include the total but are missing one type of egg (addend). This kind of problem calls for a more robust model for addition/subtraction. The egg orders are blown into a puddle and now two of the egg varieties are unknown. This is a problem that has multiple solutions— any of which could be correct. Solving these problems call for a very sound understanding of a way to represent addition. For many children, this is their first encounter with a problem that has multiple correct solutions. The story can conclude with orders that miss an addend and sum. The conversations about problems that cannot be solved is always interesting.