## Basic College Mathematics (9th Edition)

$\frac{3}{8}$
We can perform vertical addition using the same techniques as horizontal addition. The LCM of the original denominators, 4 and 8, is 8. Therefore, we can rewrite the original fractions with a denominator of 8. $\frac{1}{4}+\frac{1}{8}=\frac{1\times2}{4\times2}+\frac{1}{8}=\frac{2}{8}+\frac{1}{8}=\frac{2+1}{8}=\frac{3}{8}$