簡單事件的理論機率

Problem

Explain the theoretical probability of simple events for a Grade 7 student.

Step 1: Define Theoretical Probability

Theoretical probability helps us predict how likely an event is to happen.

To find the theoretical probability of an event, divide the number of favorable outcomes by the total number of possible outcomes:

$$P(\text{event})=\frac{\text{number of favorable outcomes}}{\text{total number of possible outcomes}}$$

Step 2: Apply the Formula

For example, suppose we want to find the probability of rolling a $4$ on a six-sided die.

There is only one favorable outcome: rolling a $4$.

There are $6$ total possible outcomes because the die has $6$ sides.

So,

$$P(\text{rolling a }4)=\frac{1}{6}$$

Step 3: Final Answer

The theoretical probability of rolling a $4$ on a six-sided die is:

$$\frac{1}{6}$$