Math 7 Unit 3 Percent Applications Review

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What is percent error?

Back

Percent error is a measure of how inaccurate a measurement is, expressed as a percentage of the true value. It is calculated using the formula: Percent Error = |(Estimated Value - Actual Value)| / Actual Value * 100.

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How do you calculate the extra amount needed when given a percentage?

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To calculate the extra amount needed, multiply the original amount by the percentage (as a decimal) and then add that to the original amount. For example, if you need 0.8 yards and want to cut an extra 25%, calculate 0.8 * 0.25 = 0.2 yards, then add: 0.8 + 0.2 = 1 yard.

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What is the formula to find the percentage of a part compared to a whole?

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The formula to find the percentage is: (Part / Whole) * 100. For example, if Jackson struck out 25 times out of 75 at bats, the percentage is (25 / 75) * 100 = 33.33%.

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What does a 90% markup mean?

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A 90% markup means that the selling price is 90% higher than the cost price. If the cost price is $100, the selling price would be $100 + ($100 * 0.90) = $190.

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How do you find 33% of a number?

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To find 33% of a number, multiply the number by 0.33. For example, to find 33% of 24 hours, calculate 24 * 0.33 = 7.92 hours, which rounds to 8 hours.

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What is the relationship between fractions and percentages?

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Fractions can be converted to percentages by dividing the numerator by the denominator and then multiplying by 100. For example, 1/4 = (1 ÷ 4) * 100 = 25%.

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How do you determine if an estimate is reasonable?

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To determine if an estimate is reasonable, compare it to the actual value and calculate the percent error. A small percent error indicates a reasonable estimate.

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What is the significance of rounding in calculations?

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Rounding is used to simplify numbers to make them easier to work with, but it can also introduce small errors. It's important to round appropriately based on the context.

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How do you calculate the selling price after a markup?

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To calculate the selling price after a markup, use the formula: Selling Price = Cost Price + (Cost Price * Markup Percentage). For example, if the cost price is $100 and the markup is 20%, Selling Price = $100 + ($100 * 0.20) = $120.

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What is the importance of understanding percentages in real life?

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Understanding percentages is important for making informed decisions in finance, shopping, cooking, and many other areas where comparisons and calculations are necessary.