In this post, we’re going to take a look at when we can use the rule of 3 as a tool to solve a problem.

The** rule of 3** is one of the most applicable and most useful mathematical phenomena, above all due to its combination of simplicity and efficiency.

We should take into account that the rule of 3 is based on the type of relationship that exists between two quantities. For example:

**In this figure, we can see that a numerical relation exists between the box and the video cameras it contains. The relation being “1 box contains 3 video cameras.”**

Knowing this, we can now solve the following problem.

**How many video cameras are there in three boxes?**

We can only solve this problem because we know the number of video cameras in each box, therefore we apply this relation to the three boxes.

“If there are 3 cameras in one box, three boxes will have the same contents as one box multiplied by 3.”

This method of reasoning is what we call in mathematics **“the rule of 3.”**

All we have done is use the information from the first situation to solve the second.

Now you know what the rule of 3 is. If you want to see more examples and practice exercises, sign up for a free trial at Smartick!

Learn More:

- Problems Involving the Inverse Rule of 3
- Rule of 3: Direct and Inverse
- Inverse Proportionality: The Rule of Three Inverse
- Rule of Three for Calculating Percentages
- Compound Rule of 3: When to Use It and Some Problems