First general score, and then compare the size of the two scores. 3 / 4 and 2 / 3, 8 / 27 and 4 / 9, 5 / 8 and 7 / 10

First general score, and then compare the size of the two scores. 3 / 4 and 2 / 3, 8 / 27 and 4 / 9, 5 / 8 and 7 / 10

The least common denominator of 3 / 4 and 2 / 3 is 12
3/4=3×3/4×3=9/12
2/3=2×4/3×4=8/12
9/12>8/12
3 / 4 > 2 / 3
The least common denominator of 8 out of 27 and 4 out of 9 is 27
8/27
4/9=4×3/9×3=12/27
8/27

First pass, then compare the size
3 / 5 and 4 / 7, 2 / 4 and 4 / 12, 7 / 12 and 3 / 8, 5 / 12 and 3 / 7

21/35〉20/35
6/12〉4/12
14/24〉9/24
35/84〈36/84

The following groups of scores, first pass, and then compare their size
5 out of 6, 4 out of 9 and 5 out of 12
11 out of 30, 7 out of 15 and 2 out of 5

6. The smallest common denominator of 9 and 12 is 36, so 5 / 6 is equal to 25 / 36, 4 / 9 is equal to 16 / 36, 5 / 12 is equal to 15 / 36, so 5 / 6 is greater than 4 / 9 and 5 / 12
The least common denominator of 30, 15 and 5 is 30, so 7 / 15 equals 14 / 30, 2 / 5 equals 12 / 30, so 7 / 15 is greater than 2 / 5 and 11 / 30