A die has six faces numbered from 1 to 6, with three of them being even numbers (2, 4 and 6). If a die is tossed once, the probability of getting an even number is 3/6 or 1/2. This can also be expressed as a decimal 0.5 or a percentage 50%.

It can be calculated as:

P(even number) = P(2) + P(4) + P(6) = (1/6) + (1/6) + (1/6) = 3/6 = 1/2