Вправи 1 - 100 » 84
(30 + 1) • 7 = 30 • 7 + 1 • 7 = 210 + 7 = 217 (30 – 1) • 7 = 30 • 7 – 1 • 7 = 210 – 7 = 203 98 • 8 = (100 – 2) • 8 = 100 • 8 – 2 • 8 = 800 – 16 = 784 39 • 5 = (40 – 1) • 5 = 40 • 5 – 1 • 5 = 200 – 5 = 195 43 • 9 = (40 + 3) • 9 = 40 • 9 + 3 • 9 = 360 + 27 = 387 71 • 6 = (70 + 1) • 6 = 70 • 6 + 1 • 6 = 420 + 6 = 426