39. Вычислите: a) (3 1/3 - 2 1/4) * 6/13 + 1; б) 5 - 3/7 * (7/9 - 7/15); в) 2 4/15 : 5 2/3 + 1 3/10

a) (10/3 - 9/4) * 6/13 + 1 = (40/12 - 27/12) * 6/13 + 1 = 13/12 * 6/13 + 1 = 1/2 + 1 = 1 1/2
б) 5 - 3/7 * (35/45 - 21/45) = 5 - 3/7 * 14/45 = 5 - 2/15 = 75/15 - 2/15 = 73/15
в) 34/15 : 17/3 + 13/10 = 34/15 * 3/17 + 13/10 = 2/5 + 13/10 = 4/10 + 13/10 = 17/10 = 1 7/10