How do you increase a number by a given percent?

To increase a number by a given percent, you first need to calculate what that percent represents in terms of the original number, and then add that value back to the original number. This is precisely what the correct answer describes.

For example, if you want to increase a number, say 100, by 20%, you first find 20% of 100, which is 20 (100 x 0.20 = 20). Then, you add this amount back to the original number: 100 + 20 = 120. This method ensures that you effectively increase the original number by the desired percentage.

This approach contrasts with simply multiplying the number by the percent or adding the percent directly without converting it into a numerical value related to the original number. Such methods would not yield the correct result when determining the increased value based on a percentage.