How do you write the probability of event A using notation?

The probability of event A is written as P(A).

In probability, we use the notation P(A) to represent the likelihood of event A occurring. The letter "P" stands for probability, and the event in question is placed inside the parentheses. For example, if you are rolling a fair six-sided die and want to find the probability of rolling a 3, you would write this as P(rolling a 3).

To calculate the probability of an event, you use the formula:

\[ P(A) = \frac{\text{Number of favourable outcomes}}{\text{Total number of possible outcomes}} \]

Let's say you have a bag containing 5 red balls and 3 blue balls, and you want to find the probability of picking a red ball. The number of favourable outcomes (picking a red ball) is 5, and the total number of possible outcomes (picking any ball) is 8. So, the probability of picking a red ball is:

\[ P(\text{red ball}) = \frac{5}{8} \]

This notation and method can be applied to any event, whether it's drawing a card from a deck, flipping a coin, or any other scenario where you need to determine the likelihood of an outcome. Understanding this notation is crucial for solving probability problems and interpreting results correctly.