What is the theoretical probability of rolling an odd number on a fair die with six faces?
3/4
1/2
1/3
1/6

In a die, there are 3 odd numbers, specifically: 1, 3 and 5.
In probability for a certain event, it is a ratio of the number of favorable outcomes over the total number of possible outcomes.

Since we have 3 favorable outcomes and 6 total possible outcomes, thus
P = 3/6 = 1/2 (in lowest term)