What is the probability of rolling a 3 on a fair six-sided die?

The probability of rolling a 3 on a fair six-sided die is 1/6.

When you roll a fair six-sided die, each of the six faces has an equal chance of landing face up. This means that the die is unbiased, and no number is more likely to appear than any other. The numbers on a standard die are 1, 2, 3, 4, 5, and 6. Since there is only one face with the number 3 on it, and there are six possible outcomes in total, the probability of rolling a 3 is the ratio of the number of favourable outcomes to the total number of possible outcomes.

To calculate this probability, you use the formula:

\[ \text{Probability} = \frac{\text{Number of favourable outcomes}}{\text{Total number of possible outcomes}} \]

In this case, the number of favourable outcomes (rolling a 3) is 1, and the total number of possible outcomes (any number from 1 to 6) is 6. So, the probability is:

\[ \text{Probability} = \frac{1}{6} \]

This fraction can also be expressed as a decimal (approximately 0.1667) or a percentage (approximately 16.67%). However, for most GCSE Maths problems, leaving the answer as a fraction is perfectly acceptable and often preferred. Understanding this basic concept of probability is essential, as it forms the foundation for more complex topics in statistics and probability theory.