4) 3 2/3 : 7 1/3 · 2 2/5

3 2/3 = 11/3, 7 1/3 = 22/3, 2 2/5 = 12/5. Выражение: (11/3) : (22/3) · (12/5) = (11/3) · (3/22) · (12/5) = (11 · 3 · 12) / (3 · 22 · 5) = 396 / 330 = 6/5 = 1 1/5.