The actual length is 20 cm, the width is 10 decimeter and the area is 20× 10=200 (square decimeter).

Estimated podium desktop1.5m2;

The actual length is 1.5m, the width is 70cm, and the area is 1.5×0.7= 1.35 (square meter).

It is estimated that one side of the pencil case is 2 square decimeters;

The actual length is 20 cm, the width is 7 cm, and the area is 20×7= 140 (square centimeter) = 1.4 (square decimeter).

It is estimated that the area of handkerchief is 4 square decimeters.

The actual side length is 2.5 decimeters and the area is 2.5×2.5=6.25 (square decimeters).

Fill in the form as follows: Say that the estimated area of the handkerchief with the cover of a math book on one side of the desk stationery box is 100 square decimeter 1.5 square meter 2 square decimeter 4 square decimeter; the measured area is 200 square decimeter 1.35 square meter 1.4 square decimeter 6.25 square meter.