This is an activity I made to match GA standards MCC.3.OA.8, and MD.6 and 7. It is related to area as well as solving story problems.
The students will need at least one if not two sheets of grid paper to show their thinking on. I copied front and back and let them do it that way.
To differentiate the lesson, I let lower kids solve two of their choice and higher kids solve three problems of their choice. They could work individually or with a partner.