He has 5, he uses 2 4/15
As you can see two is a whole number, not a fraction.
So 5-2=3 so now hou have three points of credit left, and you use 4/15.
So you change three to 2 15/15 (which actually equals three) so now you have to remove the 2 from 2 15/15 since you will only be subtracting the fraction ( the two has not disappeared, you are only removing it for the moment). So now you have 15/15 - 4/15 = 11/15. (simplify if you need to, but ln this question you wont need to simplify) Now all ypu have to do is attach the two we removed and you get the answer 2 11/15
2 11/15