6 5/4 but not sure what this would be

the way you have done it the answer would be done like this

5/4 = 1 1/4

so 6 + 1 1/4 = 7 1/4

7 1/4 = 7.25

but if you are working with time . . . normally it is written like 7:15

because 15 minutes is 1/4 of an hour.

Any questions?