Chapter 5 - Number Theory and the Real Number System - Chapter Summary, Review, and Test - Review Exercises - Page 335: 56

$\dfrac{5}{16}$

Simplify the expressions inside the parentheses using their LCD of $6$ to obtain: \begin{align*} \require{cancel} &=\frac{3}{8}\left(\frac{1\cdot3}{2\cdot 3} + \frac{1\cdot 2}{3\cdot 2}\right)\\\\ &=\frac{3}{8} \left(\frac{3}{6} + \frac{2}{6}\right)\\\\ &=\frac{3}{8} \left(\frac{5}{6}\right)\\\\ &=\frac{\cancel{3}}{8} \left(\frac{5}{\cancel{6}2}\right)\\\\ &=\frac{5}{16} \end{align*}