Learning goals: Teacher Facing Calculate the area of a region by decomposing it and rearranging the pieces, and explain (orally and in writing) the solution method. Recognize and explain (orally) that if two figures can be placed one on top one other so that they match up exactly, they must have the same area. Show that area is additive by composing polygons with a given area. Full lesson plan (warm-up, activities, synthesis, cool-down prompt) from 6.1 Area and Surface Area, Grade 6.