Question

В коробке 20 карандашей.Из них 2 карандаша-чёрные,а остальные-разноцветные.Сколько разноцветных карандашей в 4 таких коробках? Решите двумя способами.

Answer 1

1сп) 20-2=18 - цветных
18*4= 72 - цветных в 4 коробках
2сп) (20-2)*4=72

Answer 2

Problem Statement

В коробке находится 20 карандашей. Из них 2 карандаша - чёрные, а остальные - разноцветные. Сколько разноцветных карандашей в 4 таких коробках? Решите двумя способами.

Solution 1: Using Subtraction

To find the number of colored pencils in 4 boxes, we need to subtract the number of black pencils from the total number of pencils and then multiply the result by 4.

Given: - Total number of pencils in one box: 20 - Number of black pencils in one box: 2

To find the number of colored pencils in one box, we subtract the number of black pencils from the total number of pencils: 20 - 2 = 18

Now, to find the number of colored pencils in 4 boxes, we multiply the number of colored pencils in one box by 4: 18 * 4 = 72

Therefore, there are 72 colored pencils in 4 such boxes.

Solution 2: Using Multiplication

Alternatively, we can directly multiply the number of colored pencils in one box by the number of boxes.

Given: - Total number of pencils in one box: 20 - Number of black pencils in one box: 2

To find the number of colored pencils in one box, we subtract the number of black pencils from the total number of pencils: 20 - 2 = 18

Now, to find the number of colored pencils in 4 boxes, we multiply the number of colored pencils in one box by the number of boxes: 18 * 4 = 72

Therefore, there are 72 colored pencils in 4 such boxes.

Summary

In summary, there are 72 colored pencils in 4 boxes, with each box containing 20 pencils and 2 of them being black. This can be calculated by subtracting the number of black pencils from the total number of pencils and then multiplying the result by the number of boxes, or by directly multiplying the number of colored pencils in one box by the number of boxes.