If the length of a rectangular field is increased by 8 meters or the width by 5 meters, the area will be increased by 80 square meters

If the length of a rectangular field is increased by 8 meters or the width by 5 meters, the area will be increased by 80 square meters

The length of the original rectangle is 80 △ 5 = 16 meters
The width of the original rectangle is 80 △ 8 = 10m
The area of the original rectangle = 16 × 10 = 160 square meters

How to calculate 102 times 28

102x28=（100+2）x28=100x28+2x28=2856

There is an experimental field 48 meters long and 25 meters wide. A road 1 meter wide is left in the middle of the experimental field. The experimental field is divided into four parts on average. What is the area of these four parts?

(48-1) ×（25-1)÷4=282
Each area is 282 square meters