Thinking Mathematically (6th Edition)

False. The correct statement is $\frac{1}{2} + \frac{1}{5} = \frac{7}{10}$.
The statement is false, for you should not add the denominators of a fraction when adding. Note that: $\frac{1}{2} + \frac{1}{5}=\frac{5}{10} + \frac{2}{10} = \frac{7}{10}$