First of all, combined with the actual object surface, let students understand what is area, which is a closed figure and area in graphics.

Second, let students clearly distinguish the meaning expressed by length units and area units. And what is the rate of progress between their adjacent units. At the same time, let students know how the enrollment rate is obtained. That's why it is 10 and 100.

Third, let students know how big 1 square centimeter, 1 square decimeter and 1 square meter are in real life, and how to determine 1 square centimeter, 1 square meter.

4. How is the formula for calculating the area obtained? At the same time, it is clear why the formulas for calculating the perimeter and area of a rectangle are different.

Fifth, let students go to real life to find the surface area of objects.