Calculate the area of a rectangle, the length of which is 80 m and the width is 40 mm less.

Before solving the problem, let’s present the value of the length of a rectangle expressed in meters in centimeters. Since 1 m = 1000 mm, then 80 dm = 80 * 1000 mm = 80,000 mm. Since the width of the rectangle is 40 mm less than the length, the width is: 80,000 mm – 40 mm = 79960 mm. The area of the rectangle is equal to the product of length and width: S = a * b = 79960 mm * 80,000 mm = 6,396,800,000 square meters = 6396.8 square meters.
Answer: the area of the rectangle is 6396.8 square meters.