Частина 2. Номер 312

Знайди добуток.

240 • 3 = (200 + 40) • 3 = 200 • 3 + 40 • 3 = 600 + 120 = 720;

130 • 5 = (100 + 30) • 5 = 100 • 5 + 30 • 5 = 500 + 150 = 650;

320 • 3 = (300 + 20) • 3 = 300 • 3 + 20 • 3 = 900 + 60 = 960;

240 • 4 = (200 + 10) • 4 = 200 • 4 + 10 • 4 = 800 + 40 = 840;

220 • 4 = (200 + 20) • 4 = 200 • 4 + 20 • 4 = 800 + 80 = 880.