11 7/12 - 5 20/21=? 21 7/18 - 1 1/24=? 13 1/3 - 9 13/24=?

Вычислим разность смешанных чисел:

1) 11 7/12 - 5 20/21 = 11 - 5 + 7/12 - 20/21 = 6 + 7/12 - 20/21 = 6 + 7 * 7/84 - 21 * 4/84 = 6 + 49/84 - 48/84 = 6 + 1/84 = 6 1/84;

2) 21 7/18 - 1 1/24 = 21 - 1 + 7/18 - 1/24 = 20 + 7 * 4/72 - 1 * 4/72 = 20 + 28/72 - 4/72 = 20 + 24/72 = 20 + 12/36 = 20 2/6 = 20 1/3;

3) 13 1/3 - 9 13/24 = 13 - 9 + 1/3 - 13/24 = 4 + 1/3 - 13/24 = 4 + 1 * 8/24 - 13/24 = 4 + 8/24 - 13/24 = 4 - 5/24 = 3 + 24/24 - 5/24 = 3 19/24.