How to use the percent button on a calculator:
If you have a percent button on your calculator, you may be wondering how to use it or how it works. Depending on the type of calculator you have, the percent button may function in different ways.
Also, on some calculators, the answer will be displayed after pushing the [%] button while on others you will have to push the [%] button and then the [=] button.
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on your calculator (for this type of equation):
if 90 [+] 10 [%] = 99
the calculator sees the 10 [%] as 10% of 90 which is equal to 9
Thus: 90 + 9 = 99
if 90 [+] 10 [%] = 90.1
the calculator sees the 10 [%] as 10/100 which is equal to 0.1
Thus: 90 + 0.1 = 90.1
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on your calculator (for this type of equation):
only enter: 10 [%]
if 10 [%] = 0 or 10 [%] = 10
the calculator is not processing 10 [%] in a meaningful way.
if 10 [%] = 0.1
the calculator sees the 10% as 10/100 = 0.1
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Your calculator's percent button may function
in different ways depending on the type of equation entered.
10 [%] may be treated as 10% of 90 if the equation is of the form: 90 [+] 10 [%] = 99
and on the same calculator, 10 [%] (by itself) may be treated as 10/100 = 0.1 if the equation is of the form: 10 [%] = 0.1
Important: If you use the percent button, it is important to determine how it functions on your calculator for the type of equation you have before relying on the answer.
Below shows how different types of calculators perform when using the percentage button:
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Calculator A:
| 90 [+] 10 [%] = 99 |
calculates as: |
90 + (10% of 90) = 99 |
| 90 [-] 10 [%] = 81 |
calculates as: |
90 - (10% of 90) = 81 |
| 90 [x] 10 [%] = 9 |
calculates as: |
90 x (0.1) = 9 |
| 90 [/] 10 [%] = 900 |
calculates as: |
90 / (0.1) = 900 |
| 10 [%] = 0 |
calculates as: |
calculator does not process |
Notice that the [x] and [/] operators cause the percent button to function differently than the [+] and [-] operators.
For the [+] and [-] operators, the calculator sees the 10 [%] as 10% of 90 which is equal to 9.
For the [x] and [/] operators, the calculator sees the 10 [%] as 10/100 which is equal to 0.1
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Calculator B:
| 90 [+] 10 [%] = 99 |
calculates as: |
90 + (10% of 90) = 99 |
| 90 [-] 10 [%] = 81 |
calculates as: |
90 - (10% of 90) = 81 |
| 90 [x] 10 [%] = 810 |
calculates as: |
90 x (10% of 90) = 810 |
| 90 [/] 10 [%] = 10 |
calculates as: |
90 / (10% of 90) = 10 |
| 10 [%] = 0 |
calculates as: |
calculator does not process |
For the [+], [-], [x], [/] operators, the calculator sees the 10 [%] as 10% of 90 which is equal to 9.
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Calculator C:
| 90 [+] 10 [%] = 90.1 |
calculates as: |
90 + (0.1) = 90.1 |
| 90 [-] 10 [%] = 89.9 |
calculates as: |
90 - (0.1) = 89.9 |
| 90 [x] 10 [%] = 9 |
calculates as: |
90 x (0.1) = 9 |
| 90 [/] 10 [%] = 900 |
calculates as: |
90 / (0.1) = 900 |
| 10 [%] = 0.1 |
calculates as: |
10/100 which is equal to 0.1 |
For the [+], [-], [x], [/] operators, the calculator sees the 10 [%] as 10/100 which is equal to 0.1
Below is a list of some calculators and the answer they provide for:
90 [+] 10 [%] =
Texas Instruments TI-84 Plus: no percent button
Texas Instruments TI-81: no percent button
Texas Instruments TI-36X Pro: 90 [+] 10 [%] = 90.1
Texas Instruments TI-30SLR: 90 [+] 10 [%] = 99
Casio fx-9750GII: no percent button
Many simple calculators: 90 [+] 10 [%] = 99
Some calculators do not have a percent button.
If your calculator does not have a percent button and you want find the answer to a percentage problem like shown below:
90 + (10% of 90) = ?
Calculate: 10% of 90 = 10/100 x 90 = 0.1 x 90 = 9
Thus:
90 + (10% of 90) =
90 + 9 = 99
If you are not sure how to calculate 10% of 90, the
percentage calculator can help.
If you want to convert from percent to decimal:
10% = ?
Convert 10% into the fraction 10/100
10/100 equals the decimal number 0.1
If you need help converting 10 percent into a fraction or decimal number please see the
percent calculator.
In summary
The percent button does not function the same on all types of calculators and even on the same calculator the percent button may perform different functions depending on the type of equation entered. Compare your calculator's answers with the answers above to help determine how your percent button works.