1. УЗАГАЛЬНЮЄМО ВИВЧЕНЕ » 23

Обчисли зручним для тебе способом. 12 + 24 + 8 = 12 + 8 + 24 = 20 + 24 = 44; 172 – (52 + 49) = 172 – 52 – 49 = 120 – 50 + 1 = 71; (35 + 70) : 7 = 35 : 7 + 70 : 7 = 5 + 10 = 15; 160 + (70 + 140) = 160 + 140 + 70 = 300 + 70 = 370; 75 + 75 + 75 + 75 = (50 + 25) • 4 = 200 + 100 = 300; (18 + 43) + 22 = 18 + 22 + 43 = 40 + 43 = 83; 25 • 7 • 4 = 25 • 4 • 7 = 100 • 7 = 700; 5 • 78 • 2 = 78 • 5 • 2 = 78 • 10 = 780; (27 + 26) – 17 = 27 – 17 + 26 = 10 + 26 = 36.