Частина 2 — Вправи: 352

352. 1) Знайди добутки двома способами.

(5 + 3) • 9 = 8 • 9 = 72 → 5 • 9 + 3 • 9 = 45 + 27 = 72

(4 + 6) • 8 = 10 • 8 = 80 → 4 • 8 + 6 • 8 = 32 + 48 = 80

(3 + 6) • 5 = 9 • 5 = 45 → 3 • 5 + 6 • 5 = 15 + 30 = 45

2) Знайди добутки зручним для тебе способом.

(2 + 7) • 7 = 9 • 7 = 63	(5 + 5) • 100 = 10 • 100 = 1000
(4 + 5) • 10 = 9 • 10 = 90

354.

31 • 3 = 30 • 3 + 1 • 3 = 90 + 3 = 93		17 • 4 = 10 • 4 + 7 • 4 = 40 + 28 = 68
18 • 4 = 10 • 4 + 8 • 4 = 40 + 32 = 72		47 • 2 = 40 • 2 + 7 • 2 = 80 + 14 = 94
41 • 2 = 40 • 2 + 1 • 2 = 80 + 2 = 82		12 • 6 = 10 • 6 + 2 • 6 = 60 + 12 = 72
33 • 3 = 30 • 3 + 3 • 3 = 90 + 9 = 99		19 • 4 = 10 • 4 + 9 • 4 = 40 + 36 = 76

355.

12 • 2 + 12 = 12 • 3 = 10 • 3 + 2 • 3 = 30 + 6 = 36

22 • 2 + 22 = 22 • 3 = 20 • 3 + 2 • 3 = 60 + 6 = 66

12 • 3 – 13 = 10 • 3 + 2 • 3 – 13 = 30 + 6 – 13 = 36 – 13 = 23

23 • 3 – 23 = 23 • 2 = 20 • 2 + 3 • 2 = 40 + 6 = 46

14 • 4 + 36 = 14 • 4 + 9 • 4 = (14 + 9) • 4 = 23 • 4 = 20 • 4 + 3 • 4 = 80 + 12 = 92

24 • 4 – 36 = 24 • 4 – 9 • 4 = (24 – 9) • 4 = 15 • 4 = 10 • 4 + 5 • 4 = 40 + 20 = 60