10 - 3 4/5 - 5 2/3 = 9 15/15 - 3 12/15 - 5 10/15 =
= (9 - 3 - 5) + (15/15 - 12/15 - 10/15) = 1 - 7/15 = 15/15 - 7/15 = 8/15,
1 7/8 * 0,4 = 15/8 * 4/10 = 3/4 (или 0,75),
1 1/3 * 3/7 + 4/7 * 1 1/3 = 1 1/3 * (3/7 + 4/7) = 1 1/3 * 7/7 = 1 1/3 * 1 = 1 1/3