Divide the following scores first and then compare them 2 / 3 and 4 / 5 11 / 21 and 4 / 7 5 / 8 and 7 / 10

Divide the following scores first and then compare them 2 / 3 and 4 / 5 11 / 21 and 4 / 7 5 / 8 and 7 / 10

10 / 15 and 12 / 15.4/5
11 / 21 and 12 / 21 4 / 7
25 / 40 and 28 / 40 7 / 10

First general score, and then compare the size of the following groups. There is also a process
3 / 1 and 9 / 4 5 / 1 and 8 / 3 6 / 5 and 9 / 8

1. 1 / 3 = 3 / 9 < 4 / 9
2. 1 / 5 = 8 / 40, 3 / 8 = 15 / 40, 1 / 5 < 3 / 8
3. 5 out of 6 = 45 out of 54, 8 out of 9 = 48 out of 54, 5 out of 6 is less than 8 out of 9
I made it myself,

1 out of 2, 2 out of 3, 3 out of 7 and compare the size

1 / 2 = 21 / 42, 2 / 3 = 42 / 42, 3 / 7 = 18 / 42
2 / 3 > 1 / 2 > 3 / 7