3/10.
4 over 10
7/10 - 4/10 = 3/10
(7-3)/10 = 4/10 = 2/5
3/2 - 7/10 = 15/10 - 7/10 = 8/10 = 4/5
-7/10-2/5= =7/10-4/10 =-11/10 =-1.1
4/5 - 1/10...8/10 - 1/10 = 7/10
4/7 minus 3/4 is -5/28
9/10 minus 7/8 is 1/40
3 4/7 minus 1/7 is 3 3/7
It is: 4/7 minus 5/12 = 13/84
7/9 minus 3/4 is 1/36
21/30 - 8/30 = 13/30