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Write probability as a decimal

Probability can be represented as a decimal by dividing the number of favorable outcomes by the total number of equally likely outcomes, interpreting the result as a value from 0 to 1 inclusive. The decimal is equivalent to the probability’s fraction and percent forms and communicates likelihood, with 0 meaning impossible and 1 meaning certain; the scope is limited to familiar finite experiments and does not include advanced probability models or statistical inference.

Detailed Explanation: Write probability as a decimal

A probability can be written as a decimal by dividing:

probability=number of favorable outcomestotal number of equally likely outcomes\text{probability}=\frac{\text{number of favorable outcomes}}{\text{total number of equally likely outcomes}}

The favorable outcomes are the outcomes you want. The total outcomes are all possible outcomes.

Example: What is the probability of rolling an even number on a fair six-sided die?

  1. List the possible outcomes: 1,2,3,4,5,61,2,3,4,5,6. There are 66 total outcomes.

  2. Find the favorable outcomes. The even numbers are 2,4,62,4,6, so there are 33 favorable outcomes.

  3. Write the probability as a fraction:

36 \frac{3}{6}

  1. Divide the numerator by the denominator:

3÷6=0.5 3\div 6=0.5

So, the probability of rolling an even number is:

0.5\boxed{0.5}

A probability is always between 00 and 11. A probability of 00 means an event is impossible, while a probability of 11 means it is certain.

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