Skill: Write probability as a fraction

Explanation and Free Practice Resources

Probability is represented as a fraction comparing the number of favorable outcomes with the total number of equally likely outcomes in a finite sample space; the numerator identifies outcomes that satisfy the event and the denominator counts all possible outcomes. The fraction may be simplified without changing its value, and probabilities range from 0 (impossible) to 1 (certain); conditional probability and non-equally likely outcomes are beyond this scope.

On this page:

Learn “Write probability as a fraction” with a detailed explanation of the concept
Master “Write probability as a fraction” with unlimited, free practice problems
Download (or modify) a free worksheet on Write probability as a fraction you can use at home or in class with practice problems that scaffold and explore “Write probability as a fraction” from different perspectives.
Start working on adaptive units like “Probability and Counting - Single Event - Intro” or “Probability and Counting - Single Event - Practice” that introduce, teach, or practice “Write probability as a fraction” to maximize your learning.

Detailed Explanation: Write probability as a fraction

To write a probability as a fraction, use:

\text{Probability}=\frac{\text{number of favorable outcomes}}{\text{total number of possible outcomes}}

Favorable outcomes are the results you want.
Total possible outcomes are all the equally likely results.

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

List all possible outcomes: $1,2,3,4,5,6$ .
Count the total outcomes: there are $6$ .
Identify the favorable outcomes. The even numbers are $2,4,6$ , so there are $3$ favorable outcomes.
Write the fraction:

\frac{3}{6}

Simplify the fraction by dividing the numerator and denominator by $3$ :

\frac{3}{6}=\frac{1}{2}

So, the probability of rolling an even number is $\boxed{\frac{1}{2}}$ . A probability is always between $0$ and $1$ , including $0$ and $1$ .

Learn by doing: Write probability as a fraction

Click a topic below to practice the foundational skills you'll need, learn the steps, or master this skill

Your results

Practice with unlimited practice problems

Probability - Shapes, One Set of Two Shapes, Two Colors - Pick One by Color, To Fraction

Earned ?

Download/Modify Free Grade 6 'Write probability as a fraction' Worksheet

Print this free 'Write probability as a fraction' worksheet to practice this skill away from the computer. Click 'Modify' to easily customize this worksheet to your exact needs.

Units Teaching This Skill

These adaptive units introduce, teach, or reinforce this skill (Write probability as a fraction) through scaffolded problems that grow in difficulty as concepts are understood.