5/11 : 3 = 5/11 * 1/3 = 5/33
8/7 : 2 = 8/7 * 1/2 = 4/7
1/3 : 4 = 1/3 * 1/4 = 1/12
10/21 : 5 = 10/21 * 1/5 = 2/21
5/11 : 3 = 5/11 * 1/3 = 5/33
8/7 : 2 = 8/7 * 1/2 = 4/7
1/3 : 4 = 1/3 * 1/4 = 1/12
10/21 : 5 = 10/21 * 1/5 = 2/21