It isn't. 7 ninths is greater than 4 ninths just as 7 is greater than 4.
7/8 is greater.
-4
4
3/4 is greater than 7/10 3/4 = 0.75 7/10 = 0.70
4/5 is greater than 3/7
4.7 is 7/10 greater than 4
7/8 is greater.
6/7 is greater than 3/4
4/5 is greater than 7/10
-2 is greater than -4
4/7 is greater.