Percents

Front

What is a percent?

Back

A percent is a way to express a number as a fraction of 100. It is often used to compare ratios and express how much of something there is in relation to a whole.

Front

How do you calculate a percentage of a number?

Back

To calculate a percentage of a number, multiply the number by the percentage (in decimal form). For example, to find 20% of 50, calculate 50 x 0.20 = 10.

Front

What is the formula for percent of change?

Back

The formula for percent of change is: ((New Value - Old Value) / Old Value) x 100.

Front

If a shirt costs $30 and is on sale for 25% off, how much do you save?

Back

You save $7.50. (30 x 0.25 = 7.50)

Front

What is the total cost of an item after tax?

Back

To find the total cost after tax, multiply the item's price by the tax rate (in decimal form) and add it to the original price. For example, for a $50 item with a 6% tax: Total = 50 + (50 x 0.06) = $53.

Front

How do you find the original price before a discount?

Back

To find the original price before a discount, divide the sale price by (1 - discount rate). For example, if an item is $40 after a 20% discount: Original Price = 40 / (1 - 0.20) = $50.

Front

What does it mean to increase a number by a percentage?

Back

To increase a number by a percentage, multiply the number by the percentage (in decimal form) and add that amount to the original number. For example, increasing 100 by 10% means: 100 + (100 x 0.10) = 110.

Front

What does it mean to decrease a number by a percentage?

Back

To decrease a number by a percentage, multiply the number by the percentage (in decimal form) and subtract that amount from the original number. For example, decreasing 200 by 15% means: 200 - (200 x 0.15) = 170.

Front

If you have a 10% coupon on a $50 purchase, how much do you save?

Back

You save $5. (50 x 0.10 = 5)

Front

What is the percent of change from 50 to 75?

Back

The percent of change is 50%. ((75 - 50) / 50) x 100 = 50%.