You are correct that 8/8 = 1 but you are confused as to thinking that 4/9 should be a whole number .
In this problem they are giving you, you need to subtract, and it's good that you can see that 8/8 = 1 , but we can't subtract 1-4/9 because 1 is NOT in fraction form. So you need 8/8.
So 8/8-4/9 , you need a common denominator. The common denominator is 72 because 8*9 = 72.
You need to remember to multiply the same number on bottom as top. So the problem should look like 72/72-32/72
72-32 = 40
40/72 you need to simplify, so divide by 4 first
10/18 and then simply again; final answer should be 5/9
I know this is confusing but I hope I helped!
