Chapter 3 - Adding and Subtracting Fractions - 3.3 Adding and Subtracting Unlike Fractions - 3.3 Exercises - Page 219: 8

$\frac{7}{8}$

The LCD of the original denominators, 4 and 8, is 8. Therefore, we can rewrite both fractions with a denominator of 8. $\frac{5}{8}+\frac{1}{4}=\frac{5}{8}+\frac{1\times2}{4\times2}=\frac{5}{8}+\frac{2}{8}=\frac{5+2}{8}=\frac{7}{8}$