well, the idea being, he spent less time in his chemistry assigment, so 1/4 has to be less than 3/8.
so, then, let's find their difference, since 3/8 is greater, let's subtract 1/4 from it.
[tex]\bf \cfrac{3}{8}-\cfrac{1}{4}\impliedby \textit{we'll use an LCD of 8}\implies \cfrac{(1\cdot 3)~-~(2\cdot 1)}{8}
\\\\\\
\cfrac{3-2}{8}\implies \cfrac{1}{8}[/tex]
