What you’ll learn
Solve tax, tip and commission problems.
Key idea
Sales tax is usually based on the purchase price; a tip is based on the meal bill; commission is based on sales. Multiply the base by the rate written as a decimal or fraction.
If the question asks for just the tax, report the added amount. If it asks for the total, add the tax to the original bill. For a tip total, add the tip to the meal bill. Labeling both amounts prevents confusing the percent part with the final amount.
Worked example
Enter the exact value or ordered values in the format requested below.
A pre-tax purchase is $40; the tax rate is 5%. Find the tax amount alone as a dollar number, not the total with the base.
- The tax base is the pre-tax purchase $40.
- The tax amount alone is 40×5/100=$2; it is not the base plus the charge.
Answer: 2
Quick Check
Evaluate a worked attempt at solve tax, tip and commission problems, identify the first invalid step, and provide the correction.
For pre-tip meal bill $60 and 20% tip: Step 1, select $60 as the base. Step 2, tip=60×20=$1200. Locate the first invalid step and correct the amount alone.