In this lesson, students use an area model to write products as sums and sums as products. Students use the fact that the opposite of a number is the same as multiplying by -1 to write the opposite of a sum in standard form. Students recognize that rewriting an expression in a different form can shed light on the problem and how the quantities in it are related.

In this lesson, students use an area/rectangular array model and distributive property to write products as sums and sums as products. Students use the fact that the opposite of a number is the same as multiplying by -1 to write the opposite of a sum in standard form. Students recognize that rewriting an expression in a different form can shed light on the problem and how the quantities in it are related.

The instructions for the two expressions sound very similar, however, the order in which the different operations are performed and the exact wording make a big difference in the final expression. Students have to pay close attention to the wording: Ňsubtract the result from 1Ó and Ňsubtract 1 from the resultÓ are very different.

In this lesson, students recognize the identity properties of 0 and 1 and the existence of inverses (opposites and reciprocals) to write equivalent expressions.