How to write a whole number into a fraction in a subtraction problem

Im hoping you just want an example so here you go

whole number: 16
fraction version of 16: 16/1

to subtract fractions you have to have a common denominator.

so if i had a problem like     6 -1/3
step 1 would be to turn 6 into a fraction: 6/1
step 2 is to find the common denominator:
6/1 -1/3, in this case it is 3, so you multuply the first term by 3
you would then get     18/3 - 1/3,  now all you do if subract numerators, 18-3=15

final answer would be 15/3, you can simplify it into 5/1 which is also 5