вычислите удобным способом:
7/9 : (-5 1/4) : 2/27 * (-1 2/7);
8 9/13 * 5 6/7- 8 9/13 * 3 6/7 + 6 4/13 * 2

1. 7/9 : (-5 1/4) : 2/27 * (-1 2/7) = 7/9 : 21/4 : 2/27 * 9/7 = 7/9 * 4/21 * 27/2 * 9/7 = 4/21 * 27/2 = 18/7 = 2 4/7, 2. 8 9/13 * 5 6/7 - 8 9/13 * 3 6/7 + 6 4/13 * 2 = 8 9/13*(5 6/7 - 3 6/7) + 6 4/13 * 2 = 8 9/13 * 2 + 6 4/13 * 2 = 2 * (8 9/13 + 6 4/13) = 2 * (14 + 13/13) = 2 * 15 = 30