( 7 целых 1/5*2 целых 2/9)-13 4/7
(7 1/5 * 2 2/9) - 13 4/7 = 2 3/7 1) 7 1/5 * 2 2/9 = 36/5 * 20/9 = 4 * 4 = 16 2) 16 - 13 4/7 = 15 7/7 - 13 4/7 = 2 3/7