6 Найдите значение

a) (1 2/3 - 4/9) : (5/6) = (15/9 - 4/9) : 5/6 = 11/9 : 5/6 = 11/9 * 6/5 = 66/45 = 22/15

б) (9/4 - 2/3) : (9/5) = (27/12 - 8/12) : 9/5 = 19/12 : 9/5 = 19/12 * 5/9 = 95/108

в) (5/7 - 10/9) : (9/5) = (45/63 - 70/63) : 9/5 = -25/63 : 9/5 = -25/63 * 5/9 = -125/567