How to Subtract Percentages

How to Subtract Percentages
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You have two options if you have to subtract percentages as part of a math problem. With the first method, you work out the percentage value and subtract it from the original value. With the second method, you work out the remaining percentage and then calculate the percentage value. Both methods of subtracting percentages are simple, so just choose the one you prefer.

Calculate, Then Subtract

    Change the percentage to a decimal. For example, say you have a math problem asking you to work out a sale price of an item. The item's original price was $27.90 and it has 30 percent off in the sale. This means you want to subtract 30 percent from $27.90. Divide the percentage number by 100 to convert to a decimal. In this case, work out

    30 ÷ 100 = 0.3

    Multiply the original value by the decimal to determine the percentage value. In this example, work out

    27.90 × 0.3 = 8.37

    Subtract the percentage value from the original price. In this example, work out

    27.90 - 8.37 = 19.53

    The new price is $19.53.

Subtract, Then Calculate

    Take the percentage from 100 to find the remaining percentage. In the previous example, work out

    100 - 30 = 70

    The remaining percentage is 70 percent.

    Divide the remaining percentage number by 100 to convert to a decimal. In this example, work out

    70 ÷ 100 = 0.7

    Multiply the original value by the remaining percentage decimal. In this example, work out

    27.90 × 0.7 = 19.53

    The new price is $19.53.

    Tips

    • If you have a calculator with a percentage (%) key, you can subtract percentages. To subtract 30 percent from $27.90 as per the previous example, type 27.90 − 30 % = to get the answer of 19.53.

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