Percents and Proportions

Front

What is a percent?

Back

A percent is a ratio expressed as a fraction of 100. It represents a part of 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 * 0.20 = 10.

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if a/b = c/d, then a, b, c, and d are in proportion.

Front

How do you convert a fraction to a percent?

Back

To convert a fraction to a percent, divide the numerator by the denominator and multiply by 100. For example, 1/4 = (1 ÷ 4) * 100 = 25%.

Front

What is the formula to find the total amount when given a part and its percent?

Back

The formula is: Total = Part / (Percent in decimal form). For example, if 20 is 25% of a total, then Total = 20 / 0.25 = 80.

Front

If 5 is 2% of a number, how do you find that number?

Back

To find the number, use the formula: Number = Part / (Percent in decimal form). So, Number = 5 / 0.02 = 250.

Front

How do you find the percent increase?

Back

Percent increase is calculated by: ((New Value - Original Value) / Original Value) * 100. For example, if a price increases from $50 to $60, the percent increase is ((60 - 50) / 50) * 100 = 20%.

Front

What is the relationship between percents and decimals?

Back

Percents can be converted to decimals by dividing by 100. For example, 75% as a decimal is 0.75.

Front

How do you find the percent decrease?

Back

Percent decrease is calculated by: ((Original Value - New Value) / Original Value) * 100. For example, if a price drops from $80 to $60, the percent decrease is ((80 - 60) / 80) * 100 = 25%.

Front

What is the total number of hours in a week?

Back

There are 168 hours in a week (24 hours/day * 7 days/week).