One side of a square is reduced by 20%, and the other side is increased by 2 meters to get a rectangle. The area of the rectangle is equal to that of the original square, What's the area of a square? It's better to be simple and explain how each step comes from Use arithmetic

One side of a square is reduced by 20%, and the other side is increased by 2 meters to get a rectangle. The area of the rectangle is equal to that of the original square, What's the area of a square? It's better to be simple and explain how each step comes from Use arithmetic

(additional: the red part plus the green part equals the original square)
Draw a picture to know the general situation: the green part = the blue part (the area of this rectangle is equal to that of the original square, and the red part is the common part)
We can know from the question: the ratio of the width of the green part and the red part is 0.2:0.8 = 1:4, and we can clearly see the appearance of the green part and the red part, so the ratio of the area of the green part and the red part is 1:4. Then, we know that the green part = the blue part, that is, the ratio of the area of the red part and the blue part is 4:1
Now, looking at the boundary between the red part and the blue part, we can see that the width of the two parts is equal (the length of the blue part is regarded as the width first, and the width of the blue part is regarded as the length first, so as to understand it.) and we know that the area ratio of the two parts is 4:1, then the length side ratio of the two parts is 4:1
At this point, it's too easy. The long side of the blue part is known as 2m, and the red part is 2 × 4 = 8m
OK, 8 × 8 = 64 square meters
The above sources are calculated as follows:
  【2÷（20%/80%）】²
=【2×4】²
=8²
=64（㎡）