# How to Calculate Percentages & Formulas With a Calculator

by Melvin Richardson; Updated September 26, 2017Your calculator can perform many formulas as well as percentages. When you use a calculator it helps you save time by helping you find the answer to a variety of transactions. If you want to perform percentages and other formulas you must become familiar with all of the keys on the calculator. Certain transactions can be completed in different ways. A calculator provides you with the ability to add, divide, subtract and multiply, quickly and efficiently.

Locate the percentage key. If you want to perform or calculate percentages you need to use the percentage key (%), on your calculator. To find a percentage of a number, key in the number in your calculator and then hit the multiply key. If you want to find out what 10 percent of the number is key in 10 and then hit the percent key. The answer will be displayed on your calculator (1020 x 10 % = 102). Therefore 10 percent of 1,020 equals 102. You can also calculate percentages by entering the percent in the form of a decimal. Enter .10 (10 percent) and then hit the multiply key and then the number you are trying to find a percent of and then the equal key (.10 x 1020 = 1020).

Find the addition key. If you want to add using a calculator you will first enter a number you want to add then hit the addition key, (+) and enter the next number and then hit the equal key and your answer will be displayed (45 + 73 = 118). When there is more than two numbers to add, hit the addition or plus key every time a number is entered and when the last number has been entered hit the equal key.

Locate the subtraction key. Calculators also allow you to subtract numbers. First enter the number you want to subtract from and then hit the subtract key (-), and enter the number to be subtracted from the first and hit the equal key (100 - 25 = 75).

Locate the multiplication key on your calculator. Enter the number you want to multiply another number by and then hit the multiply key and then enter the second number and hit the equal key (100 x 25 = 2,500).

Find the division key. Enter the number you want to be divided and then hit the division key (/). Key in the number that is to be divided, into the first and hit the equal key to get your answer (450 / 50 = 9).

Perform calculations involving more than one action. You can perform calculations that allow you to perform two or more calculations, such as addition and division. Enter 450 and hit the addition key and enter the number to be added (25), and now hit the division key and enter the next number (25), and then hit the equal key to receive the answer of 19 (450 + 25 / 25 = 19).

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- Calculator image by Alhazm Salemi from Fotolia.com