Chapter 11 - Probability and Statistics - 11-3 Probability of Multiple Events - Practice and Problem-Solving Exercises - Page 693: 52

$\dfrac{1}{2}$

In a roll of a die, there are $6$ possible outcomes. Since there are $3$ events corresponding to rolling an even number (rolling a $2$ or a $4$ or a $6$), then the probability of rolling an even number is \begin{align*}\require{cancel} P(even)&= \dfrac{3}{6} \\\\&= \dfrac{\cancel3^1}{\cancel6^2} \\\\&= \dfrac{1}{2} .\end{align*}