Answer
$\frac{1}{2}$
Work Step by Step
There are 6 possible outcomes of tossing a single die: 1, 2, 3, 4, 5, 6.
The even numbers, 2, 4, 6, represent 3 of the 6 possible outcomes, so the probability is 3 out of 6.
$\frac{3}{6}=\frac{3\div 3}{6\div 3}=\frac{1}{2}$