7/25 is a proper fraction and there is no sensible way to write it as an improper fraction.
-25/1
0.280 as a fraction is 7/25
You could write it as 25/1.
12.5 as an improper fraction is 25/2
6.12 in fraction form is 153/25
25% is 25/100 or 1/4
25% = 25/100 = 1/4
12/25
6/25
4/25
-132/25