Solve the following arithmetic problems: Б 1) 72 : 8 + 81 : 30 + 17 2) 3 · 50 - 20 : 13 + 90 3) 99 + 101 : 20 · 6 - 15 4) 520 - 330 · 2 + 20 : 100

Решение:

Задание 1:

1. \( 72 : 8 = 9 \)
2. \( 9 + 81 = 90 \)
3. \( 90 : 30 = 3 \)
4. \( 3 + 17 = 20 \)

Задание 2:

1. \( 3 \times 50 = 150 \)
2. \( 150 - 20 = 130 \)
3. \( 130 : 13 = 10 \)
4. \( 10 + 90 = 100 \)

Задание 3:

1. \( 99 + 101 = 200 \)
2. \( 200 : 20 = 10 \)
3. \( 10 \times 6 = 60 \)
4. \( 60 - 15 = 45 \)

Задание 4:

1. \( 520 - 330 = 190 \)
2. \( 190 \times 2 = 380 \)
3. \( 380 + 20 = 400 \)
4. \( 400 : 100 = 4 \)

Ответ: 1) 20, 2) 100, 3) 45, 4) 4.