Model decompositions of 3 with materials, drawings, and expressions. Represent the decomposition as 1 + 2 and 2 + 1.

In this lesson, students continue to decompose numbers. They begin by modeling the decomposition of numbers three, four, and with manipulatives and a number story. Then they model the decomposition of number 3 by drawing. They match their drawing to the corresponding number card and represent the decomposition using the expressions ___ + ___.