Geometric measurement: understand concepts of area and relate to area of multiplication and addition.
Relate area to the operations of multiplication and addition. (3.MD.7)
Recognize area as additive. Find areas of rectilinear figures by decomposing them into non-overlapping rectangles and adding the areas of the non-overlapping parts, applying this technique to solve real world problems. (3.MD.7d)
More information and the complete College and Career Readiness Standards can be found here.