1/4 * 100:75=25/75=1/3 - искомое число
9/10:9/5*1/6=1/5*1/6=1/30
2,4/7*5,1/4:1,1/8=
1) 2,4/7*5,1/4=18/7*21/4=13,1/2
2)13,1/2:1,1/18=13,15/19
1 1/2 * 2 2/11 + 2 3/4 * 2 2/11 - 2 2/11 * 3 5/6 = 3/2 * 24/11 + 11/4 * 24/11 - 24/11 * 23/6 = 36/11 + 6/1 - 92/11 = (36+66-92)/11 = 10/11