Chapter 5 - Number Theory and the Real Number System - 5.3 The Rational Numbers - Exercise Set 5.3 - Page 285: 72

$\dfrac{ 7 }{ 13 }$

To combine fractions, make sure that the fractions have the same denominators before combining their numerators. \begin{align} \dfrac{ 5 }{ 13 } + \dfrac{ 2 }{ 13 } &= \dfrac{ 5 + 2 }{ 13 } &&\text{Add the numerators} \\ &= \boxed{ \dfrac{ 7 }{ 13 } } \end{align}