Question: how to add and subtract percentages?
Answer: If your calculator does not have a percent key and you want to add a percentage to a number multiply that number by 1 plus the percentage fraction. For example 25000+9% = 25000 x 1.09 = 27250. To subtract 9 percent multiply the number by 1 minus the percentage fraction. Example: 25000 - 9% = 25000 x 0.91 = 22750.