Пошаговое объяснение:
5 4/5 - 2 3/20 = 29/5 - 43/20 = (29*4-43)/20 = 73/20 = 3 13/20
5/6 : 2 2/9 = 5/6 : 20/9 = 5/6 * 9/20 = 3/8
2/3•1 2/7 = 2/3 * 9/7 = 6/7
