7. В каждом столбике найди значение второго выражения, используя значение первого. 1) 9 * 7 = 63 7 * 10 = 70 15 * 4 = 60 9 * 8 7 * 9 15 * 5 2) 12 * 4 = 48 14 * 5 = 70 18 * 4 = 72 12 * 5 14 * 4 18 * 3

Решение: 1) 9 * 7 = 63, 9 * 8 = 9 * (7 + 1) = 9 * 7 + 9 * 1 = 63 + 9 = 72 7 * 10 = 70, 7 * 9 = 7 * (10 - 1) = 7 * 10 - 7 * 1 = 70 - 7 = 63 15 * 4 = 60, 15 * 5 = 15 * (4 + 1) = 15 * 4 + 15 * 1 = 60 + 15 = 75 2) 12 * 4 = 48, 12 * 5 = 12 * (4 + 1) = 12 * 4 + 12 * 1 = 48 + 12 = 60 14 * 5 = 70, 14 * 4 = 14 * (5 - 1) = 14 * 5 - 14 * 1 = 70 - 14 = 56 18 * 4 = 72, 18 * 3 = 18 * (4 - 1) = 18 * 4 - 18 * 1 = 72 - 18 = 54