MGSE3.OA.8. Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding. MGSE3.OA.9. Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations. MGSE3.MD.5. Recognize area as an attribute of plane figures and understand concepts of area measurement. MGSE3.MD.6. Measure areas by counting unit squares (square cm, square m, square in, square ft, and improvised units). MGSE3.MD.7. Relate area to the operations of multiplication and addition. MGSE3.MD.8 Solve real world problems involving perimeters of polygons, including finding the perimeter given the side lengths, finding an unknown side length, and exhibiting rectangles with the same perimeter and different areas o with the same area and different perimeters.