9 - 7 3/8 = ? You could borrow: 8 + 1 - 7 3/8. Subtract 7 from 8 and get 1; subtract 3/8 from 1 and get 5/8. This leaves you with 1 5/8. Note how I have subtracted the integer 7 from the integer 9 and then the fraction 3/8 from the whole number 1.
Alternatively, you could write 9 as 72/8 and 7 3/8 as 59/8. Subtract 59/8 from 72/8 and get 13/8, which is equal to 1 5/8 (same answer as before).
Alternatively, you could write 9 as 9.000 and 7 3/8 as 7.375. Then 9.000-7.375 = 1.625 = 1 5/8 (same answer as before).