10/30 + 9/30 = 19/30
19/30 * 9/30 = 19/100
19/30 - 6/30 = 13/30
29/30 - 13/30 = 8/15
2/10 + 4/10 = 3/5
3/5 * 2/10 = 4/5
6/10 + 4/5 = 1 2/5
9/10 - 1 2/5 = 2 3/10
Пошаговое объяснение:
