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Applying Percents

Mathematics, Grade 8

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Example: What is the sales tax on a $120 purchase, if the tax rate is 8.5%? • Percent means “out of each hundred.” It is a ratio that compares a number to 100. • Percents are often used in business, banking and everyday math problems to determine sales tax, interest, discounts and commissions. • Sales tax is a percent of the purchase price that a store collects. • Convert the tax rate to a decimal and multiply it by the purchase amount. • A discount is the amount by which the regular purchase price is reduced. • Simple interest is charged when you borrow money or paid when you invest your money. Cross multiply. Divide by 100 to isolate the variable. Cross multiply. Divide by 70 to isolate the variable. Divide by 0.15 to isolate the variable. Write the percent as a decimal. • To solve a problem with a percent, convert the percent to a decimal. • To convert a percent to a decimal, move the decimal point two decimal places to the left. Example: Example: Solving Problems with Percents Determining the Percent of a number Using Proportions Using Equations 35 is what percent of 70? 36 is 15% of what number? What is 57% of 80? 57% of 80 is 45.6 I = $40.50 I = P • r • t I = 600 • 0.045 • 1.5 Sales Tax = $10.20 0.085 x 120 = 10.20 Sale Price = 145 – 21.75 = 0.15 x 145 = x = $21.75 Sale Price = $123.25 Discount Simple Interest Sales Tax Converting Percent to a Decimal whole part whole part 57 100 m 80 = 4,560 100 100 100m = 57 • 80 100 • m = 45.6 m = 4,560 100m = 75% 0.75 35 is 50% of 70 m 100 35 70 = m • 70 100 • 35 = 36 0.15 • m = 36 15% • m = 50 m = 36 is 15% of 240 m 240 = 3,500 70m = 70 70 70m = 3,500 0.15 0.15 36 = 0.15 • m What is the interest paid on a $600 loan for 18 months at 4.5%? How much would you pay for an item if it is discounted 15% from its regular price of $145? Amount of Discount Amount of Discount Tax Rate Purchase Amount Discount Rate Regular Price = Amount of Discount Regular Price Sale Price – simple interest annual interest rate time in years principal substitute 1.5 years for 18 months substitute 0.045 for 4.5% x Sales Tax = © Copyright NewPath Learning. All Rights Reserved. 93-4807 www.newpathlearning.com Applying Percents

\|xiBAHBDy01664pzY Example: What is the sales tax on a $120 purchase, if the tax rate is 8.5%? • Percent means “_________________________.” It is a ratio that compares a number to . • Percents are often used in _______________ __________________________________________ _________________________________ _________________________________. • Sales tax is a __________ _______________________ _______________________. • Convert the tax rate to a decimal and multiply it by the purchase amount. • A discount is _______________________ _______________________. • Simple interest is ____________ _____________________________ _____________________________. Cross multiply. Divide by to isolate the variable. Cross multiply. Write the percent as a decimal. • To solve a problem with a percent, convert the percent to a decimal. • To convert a percent to a decimal, move the decimal point places to the . Example: Example: Divide by to isolate the variable. Divide by to isolate the variable. Solving Problems with Percents Determining the Percent of a number Using Proportions Using Equations 35 is what percent of 70? 36 is 15% of what number? What is 57% of 80? 57% of 80 is I = $ I = P • r • t I = 600 • 0.045 • 1.5 Sales Tax = $ Sale Price = – = 0.15 x = x = $21.75 Sale Price = $ Discount Simple Interest Sales Tax Converting Percent to a Decimal whole part whole part 57 100 m 80 = m = m = 75% 0.75 35 is % of 70 m 100 35 70 = m = 36 is 15% of What is the interest paid on a $600 loan for 18 months at 4.5%? How much would you pay for an item if it is discounted 15% from its regular price of $145? Amount of Discount Amount of Discount Tax Rate Purchase Amount Discount Rate Regular Price = Amount of Discount Regular Price Sale Price – simple interest annual interest rate time in years principal x Sales Tax = x = • • = = = • • = • = = = = 36 15% • m = • Key Vocabulary Terms • cross multiply • decimal • decimal point • discount • equation • interest • percent • proportion • ratio • tax • variable © Copyright NewPath Learning. All Rights Reserved. 93-4807 www.newpathlearning.com Applying Percents

Applying Percents

Mathematics, Grade 8

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