To find the percentage increase or decrease from one number to another there are 3 steps.
Step 1. Subtact the old number from the new.
For example, we are looking for the percentage increase from 2 to 5. In this case the old number is 2 and the new number is 5. It will look like the following:
5 - 2 = 3
Step 2. Divide the difference (the results from Step 1) by the old number.
3 / 2 = 1.5
Step 3. Multiply results from Step 2 by 100
1.5 * 100 = 150% increase.
Sample Percentage Problems
An example of a percentage problem is as follows:
Mary had a quiz in school and got 9 out of 10 problems correct. What percentage did she get correct. To solve this problem you would divide 10 by 9 (or 9/10... or 9 over 10). The answer is 90%.
Dan was at bat 4 times in the game. He hit the ball 3 times and struck out once. What is the percentage of times that he hit the ball? He hit the ball 3 out of 4 times, so it would be 3/4. The answer is 75%