Science, Tech, Math › Math Learn How to Calculate Sales Tax Share Flipboard Email Print Hero Images/Getty Images Math Math Tutorials Geometry Arithmetic Pre Algebra & Algebra Statistics Exponential Decay Functions Worksheets By Grade Resources View More By Jennifer Ledwith Math Expert B.B.A., Finance and Economics, University of Oklahoma Jennifer Ledwith is the owner of tutoring and test-preparation company Scholar Ready, LLC and a professional writer, covering math-related topics. our editorial process Jennifer Ledwith Updated January 22, 2018 One of the most common types of percent problems you'll encounter in daily life is calculating sales tax. It's not hard to do. Here's an example of how a student worked through percent and sales tax problems and tips on how you can learn to master the technique, too. Student With Sales Tax Problems I was tutoring Jason (not his real name), to prepare him for Algebra. He attended tutoring on the Internet with the help of his high-speed internet connection, web camera, computer, and graphing calculator. Thankfully, all of the technology was functioning properly and we were on our way to higher grades. "Today," I began, "we are going to review percents and sales tax.""Ok, Ms. Jennifer, I got this. I know all about sales tax." Jason confidently announced as he pulled out a pen."Oh no, Jason. Where is your pencil?""Pencil?" Jason was puzzled about a ten cent pencil, yet he sat in a maze of hundreds of dollars of gadgets."Yes, Jason, a pencil. You know that we do not do math in pen.""Yes ma'am." Jason hunted down a pencil and sharpened it with a butter knife. A hand sanitizer gel spill had ruined his pencil sharpener but rendered it 99.9% germ-free. Calculating Sales Tax After Jason put away his primitive sharpening tool, we talked about a printer that he was planning to buy. At $125, the printer was a bargain, but I emphasized that he needed to know the true amount to stay within his budget. If the sales tax rate was 8%, then how much would he pay in sales tax for the printer? What do you know?The sales tax rate is 8% or 8 percent. Realize that 8 percent means 8 per 100.8% = 8/100The printer cost $125.00With percents, think part/whole.8 (part)/100 whole = x (the part, or the sales tax amount is unknown) /125 (the whole)8/100 = x/125Cross multiply. Hint: Write these fractions vertically to get the full understanding of cross multiplying. To cross multiply, take the first fraction's numerator and multiply it by the second fraction's denominator. Then take the second fraction's numerator and multiply it by the first fraction's denominator.8 * 125 = x * 1001000 = 100xDivide both sides of the equation by 100 to solve for x.1000/100 = 100x/10010 = xVerify the answer.Does 8/100 = 10/1258/100 = .0810/125 = .08 So, he would spend $135 ($125 + $10) on a $125 printer. Note: Add $125 and $8 to get the total amount. Remember, the sales tax is 8% of the price, not $8. Answers and Explanations Original Worksheet Sales Tax Percent Example Calculations 1. Laptop Bag Price: $18Sales tax rate: 9%Sales tax amount:$1.62Final cost: $19.62 What do you know?9/100 = x/18 Cross Multiply and Solve.9 * 18 = x * 100162 = 100x162/100 = 100x/100$1.62 = xVerify the Answer. Does 9/100 = 1.62/18?9/100 = .091.62/18 = .09$1.62 + $18 = $19.622. Anti-Virus SoftwarePrice: $50Sales tax rate: 8.25%Sales tax amount: $4.125Final cost: $54.13 What do you know?8.25/100 = x/50 Cross Multiply and Solve.8.25 * 50 = x * 100412.50 = 100x412.50/100 = 100x/100$4.125 = xVerify the Answer. Does 8.25/100 = 4.125/50?8.25/100= .08254.125/50= .0825$4.125 + $50 ≈ $54.13 3. USB DrivePrice: $12.50Sales tax rate: 8.5% Sales tax amount: $1.0625Final cost: $13.56 What do you know?8.5/100 = x/12.50 Cross Multiply and Solve.8.5 * 12.50 = x * 100106.25 = 100x106.25/100 = 100x/100$1.0625 = xVerify the Answer. Does 8.5/100 = 1.0625/12.50?8.5/100= .0851.0625/12.50 = .085$12.50 + $1.0625 ≈ $13.56 4. Graphing CalculatorPrice: $95Sales tax rate: 6%Sales tax amount: $5.70Final cost: $100.70 What do you know?6/100 = x/95 Cross Multiply and Solve.6 * 95 = x * 100570 = 100x570/100 = 100x/100$5.70= xVerify the Answer. Does 6/100 = 5.70/95?6/100= .065.70/95= .06$95 + $5.70 = 100.70 5. MP3 Player Price $76Sales tax rate: 10%Sales tax amount: $7.60Final cost: $83.60 What do you know?10/100 = x/76 Cross Multiply and Solve.10 * 76 = x * 100760 = 100x760/100 = 100x/100$7.60 = xVerify the Answer. Does 10/100 = 7.60/76?10/100= .107.60/76 = .10$76 + $7.60 = $83.60 6. Laptop ComputerPrice: $640Sales tax rate: 8.5%Sales tax amount: $54.40Final cost: $694.40 What do you know?8.5/100 = x/640 Cross Multiply and Solve.8.5 * 640 = x * 1005440 = 100x5440/100 = 100x/100$54.40 = xVerify the Answer. Does 8.5/100 = 54.40/640?8.5/100= .08554.40/640 = .085$640 + $54.40 = $694.40 Cite this Article Format mla apa chicago Your Citation Ledwith, Jennifer. "Learn How to Calculate Sales Tax." ThoughtCo, Aug. 26, 2020, thoughtco.com/percent-calculate-sales-tax-answers-2312478. Ledwith, Jennifer. (2020, August 26). Learn How to Calculate Sales Tax. Retrieved from https://www.thoughtco.com/percent-calculate-sales-tax-answers-2312478 Ledwith, Jennifer. "Learn How to Calculate Sales Tax." 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