1. Проверь, верны ли равенства. 13.(10+2) = 13.10 + 13.2 (20+5) ・4=20+5・4 15. (102) = 15.10.2 72: (83) = 72:8.3

1) 13 ⋅ (10 + 2) = 13 ⋅ 10 + 13 ⋅ 2

• Левая часть: 13 ⋅ (10 + 2) = 13 ⋅ 12 = 156
• Правая часть: 13 ⋅ 10 + 13 ⋅ 2 = 130 + 26 = 156
• Вывод: 156 = 156, равенство верно.

2) (20 + 5) ⋅ 4 = 20 + 5 ⋅ 4

• Левая часть: (20 + 5) ⋅ 4 = 25 ⋅ 4 = 100
• Правая часть: 20 + 5 ⋅ 4 = 20 + 20 = 40
• Вывод: 100 ≠ 40, равенство неверно.

3) 15 ⋅ (10 ⋅ 2) = 15 ⋅ 10 ⋅ 2

• Левая часть: 15 ⋅ (10 ⋅ 2) = 15 ⋅ 20 = 300
• Правая часть: 15 ⋅ 10 ⋅ 2 = 150 ⋅ 2 = 300
• Вывод: 300 = 300, равенство верно.

4) 72 : (8 ⋅ 3) = 72 : 8 ⋅ 3

• Левая часть: 72 : (8 ⋅ 3) = 72 : 24 = 3
• Правая часть: 72 : 8 ⋅ 3 = 9 ⋅ 3 = 27
• Вывод: 3 ≠ 27, равенство неверно.