Частина 1 — Вправи: 157

157. Обчисли зручним способом. Використай відомі тобі закони дій.

54 ● 9 + 46 ● 9 = (54 + 46) ● 9 = 100 ● 9 = 900

27 ● 5 + 23 ● 5 = (27 + 23) ● 5 = 50 ● 5 = 250

330 ● 3 – 3 ● 330 = (330 – 330) ● 3 = 0 ● 3 = 0

5 ● 170 – 3 ● 30 = 5 ● (100 + 70) – 90 = 500 + 350 – 90 = 760

54 ● 9 – 46 ● 9 = (54 – 46) ● 9 = 8 ● 9 = 72

27 ● 5 – 23 ● 5 = (27 – 23) ● 5 = 4 ● 5 = 20

0 ● 100 + 3 ● 150 = 3 ● (100 + 50) = 300 + 150 = 450

137 ● 11 ● 0 : 54 = 0 : 54 = 0

8 ● 87 + 8 ● 13 = 8 ● (87 + 13) = 8 ● 100 = 800

72 ● 10 – 72 ● 9 = 72 ● (10 – 9) = 72 ● 1 = 72

1 ● 2 ● 3 ● 4 ● 5 ● 6 ● 7 ● 0 = 0

0 : 8 : 9 : 10 : 11 = 0