Answer :

I like to do these by subtracting the whole numbers and fractions separetely. 

17 8/12 = 17 + 8/12 
12 3/12 = 12 + 3/12

17 + 8/12 - 12 - 3/12 
17 - 12 + 8/12 - 3/12
5 + 5/12
= 5 5/12

17 8/12 - 12 3/12 = 5 5/12
Lyici
The answer is 5 wholes and 5/12 because when you line it up 17 8/12 12 3/12 5 5 /12