Calculating the percentage of a given number is a very common math problem to solve. In this article, we'll cover how to calculate what 3% of 21 is, and give you step-by-step instructions so you can learn how to do it yourself as well.

Looking for percentage worksheets? Click here to see all of our free percentages worksheets.

There are only two steps you need to follow in order to find 3% of 21. We'll start by dividing the number, 21, by 100.

We do this because percent means one part in every hundred, and since this is what we need to calculate in this problem, it's the first step in the process:

At this point, we know that 1% of 21 is 0.21, because we just divided it by 100. I'm sure you've guessed now that all we need to do is multiply our result, 0.21, by the percentage we want to find, which is 3:

(Note that we have rounded the final answer down to two decimal places)

As you can see, the actual process of calculating 3 percent of 21 is incredibly simply and straightforward to do. We can now easily see that **3% of 21 is 0.63**.

## Why Calculate the Percentage of a Number?

Percentages are very useful to make calculations easier and to understand numbers and the differences between them. It's much simpler to work with and understand parts of 100 than it is to use fractions that often do not have an exact, non-recurring, decimal equivalent.

Since a percentage is really just a fraction where the denominator is 100, comparisons are easier too.

For working out the percentage of a number, like 3% of 21, we do these types of calculation all the time in real life. A few examples might be:

- A customer trying to calculate how much a sale item costs in a store
- A business looking to analyze their net and gross profit margins
- Computer software will lets you know how long there is left in the installation

## Practice Percentage Worksheets

Like most math problems, percentages is something that will get much easier for you the more you practice the problems and the more you practice, the more you understand.

Whether you are a student, a parent, or a teacher, you can create your own percentage worksheets using our percentages worksheet generator. This completely free tool will let you create completely randomized, differentiated, percentage problems to help you with your learning and understanding of percentages.

## Practice Percentages of Numbers Using Examples

If you want to continue learning about how to calculate the percentage of a number, take a look at the random calculations in the sidebar to the right of this blog post.

We have listed some completely random percentage of a number examples that you can follow along with to help you work through a number of problems.

Each article will show you, step-by-step, how to work out the percentage of the given number and will help students to really learn and understand this process.

## Calculate Another Percentage Difference

Enter your numbers into the boxes below below and click "Calculate" to work out the percentage of the number.