Enter the number of ways to do one thing and the number of ways to do another thing into the calculator to determine the total number of outcomes or possibilities. This calculator can also evaluate any of the variables given the others are known.

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## Counting Rule Formula

The following formula is used to calculate the number of outcomes or possibilities in an event or experiment using the Counting Rule.

CR = m * n

Variables:

- CR is the total number of outcomes or possibilities
- m is the number of ways to do one thing
- n is the number of ways to do another thing

To calculate the total number of outcomes or possibilities, multiply the number of ways to do one thing by the number of ways to do another thing. This is based on the multiplication principle of the Counting Rule in combinatorics.

## What is a Counting Rule?

A Counting Rule, in probability and statistics, is a guideline or formula that helps to determine the number of outcomes or possibilities in an event or experiment. It is used in combinatorics to calculate combinations and permutations, which are essential in probability theory. The basic counting rule, also known as the multiplication principle, states that if there are ‘m’ ways to do one thing and ‘n’ ways to do another, then there are m*n ways to do both.

## How to Calculate Counting Rule?

The following steps outline how to calculate the Counting Rule using the formula CR = m * n.

- First, determine the value of m, which represents the number of ways to do one thing.
- Next, determine the value of n, which represents the number of ways to do another thing.
- Next, use the formula CR = m * n to calculate the total number of outcomes or possibilities.
- Finally, calculate the Counting Rule.
- After inserting the values of m and n and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

m = 5

n = 3