Solution
For this case we assume that the total is represented by 1
We know that Carlos use 5/8 for the first box and 1/4 for the second box, so we can do this:
[tex]1-\frac{5}{8}-\frac{1}{4}=\frac{1}{8}[/tex]And that represent the fraction of paper remaining then the answer is given by:
[tex]1-\frac{1}{8}=\frac{7}{8}[/tex]Carlos uses 7/8 of the paper to wrap the two boxes