firstly let's convert the mixed fraction to improper fraction and then subtract it from 5.
[tex]\stackrel{mixed}{1\frac{1}{8}}\implies \cfrac{1\cdot 8+1}{8}\implies \stackrel{improper}{\cfrac{9}{8}} \\\\[-0.35em] ~\dotfill\\\\ 5-\cfrac{9}{8}\implies \cfrac{5}{1}-\cfrac{9}{8}\implies \cfrac{(8)5~~ - ~~(1)9}{\underset{\textit{using this LCD}}{8}}\implies \cfrac{40-9}{8}\implies \cfrac{31}{8}\implies 3\frac{7}{8}[/tex]
