Найти значение выражения. 3/10: (2/5+3/15), 4/7*5/24: 1 1/14, 25*7/15: 7/9, 7/18: 20/21: 5/12, 5/9*2 1/4: 20

3/10 :(2/5+3/15)=3/10:9/15=3/6=1/2
4/7 * 5/24 : 1 1/14 = 5/42 :15/14 = 1/9
25 * 7/15 : 7/9 = 35/3 * 9/7 = 15
7/18 : 20/21 : 5/12 = 7/18 * 21/20 : 5/12 = 147/360 * 12/5 = 147/150
5/9 * 2 1/4 :20 = 5/9 * 9/4 : 20=5/4 * 1/20= 1/16