8/10 can be simplified to 4/5 which is .8; 5/4 is 1.25 (12.5/10).
Any fraction between 8/10 and 12.5/10 will work:
9/10
10/10 or 1
11/10 or 1 1/10
85/100 or 17/20
95/100 or 19/20
To find a fraction between two fractions, all we need to do is make the sum of the numerators be the new numerator, and the sum of the denominators be the new denominator. So, for example, a fraction between 7/13 and 6/11 is (7 + 6)/(13+ 11) =13/24.
7/13 = .5384615...
6/11 = .545454...
13/24 = .541666...
Get more info on finding a fraction between two fractions from www.math.nmsu.edu.