Rates, Ratios, Percentages

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What is a ratio?

Back

A ratio is a comparison of two quantities, showing how many times one value contains or is contained within the other.

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What is a rate?

Back

A rate is a specific kind of ratio that compares two different units, such as miles per hour or cost per item.

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What is a percentage?

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A percentage is a way of expressing a number as a fraction of 100, often used to compare proportions.

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How do you calculate a percentage of a number?

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To calculate a percentage of a number, multiply the number by the percentage (as a decimal). For example, 35% of 70 is 70 * 0.35 = 24.5.

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What does '25% off' mean?

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'25% off' means that the price is reduced by 25% of the original price. For example, if an item costs $48, a 25% discount would reduce the price by $12.

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How do you find the original price after a discount?

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To find the original price after a discount, divide the sale price by (1 - discount rate). For example, if the sale price is $36 and the discount is 25%, the original price is $36 / 0.75 = $48.

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What is the formula for calculating a unit rate?

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The formula for calculating a unit rate is: Unit Rate = Total Quantity / Number of Units. For example, if 3 pizzas cost $4.50, the unit rate is $4.50 / 3 = $1.50 per pizza.

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How do you set up a ratio table?

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A ratio table is set up by listing pairs of equivalent ratios in rows. For example, to find how many batches of cookies to make for 100 cookies, you can list batches and total cookies.

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What is the relationship between ratios and fractions?

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Ratios can be expressed as fractions. For example, a ratio of 2:3 can be written as the fraction 2/3.

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How do you convert a fraction to a percentage?

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To convert a fraction to a percentage, divide the numerator by the denominator and multiply by 100. For example, 1/4 = 0.25 * 100 = 25%.