Calculate, Then Subtract

1. Find the Decimal

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.

2. Find the Percentage Value

Multiply the original value by the decimal to determine the percentage value. In this example, work out 27.90 x 0.3 = 8.37.

3. Subtract the Percentage Value

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

1. Subtract the Percentage

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.

2. Find the Decimal

Divide the remaining percentage number by 100 to convert to a decimal. In this example, work out 70 ÷ 100 = 0.7.

3. Multiply by the Decimal

Multiply the original value by the remaining percentage decimal. In this example, work out 27.90 x 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.