First find a common denominator so how can you change 4 and 8 to be the same, multiply 4 by 2 and what you do to the bottom you have to do to the top. You should get 6/8. So, usually you would change the mixed number to an improper fraction but for this problem you don’t need to. Now you would subtract 1 7/8 -6/8 and that would be 1 1/8. Sometimes you need to simply you final answer but right now it’s already at the lowest it can go. Answer : 1 1/8 Hope this helped :)