Sales tax is a percentage added at the register. A $50 item with 8% tax costs $54.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
A faster method
Multiply by 1.08 rather than computing the tax and adding it. One step instead of two.
Tips
A tip is a percentage of the bill before tax. Fifteen to twenty percent is the usual range for table service.
A mental method
Ten percent is the decimal point moved one place. Half of that is 5%, so 15% is the two added together.
Working backwards
To recover the pre-tax price from a total, divide rather than subtract. A $54 total at 8% tax means 54 ÷ 1.08 = $50.
The subtraction error
Subtracting 8% from the total gives $49.68, not $50. Percentages taken from different bases are not reversible by subtraction.
Sales tax is added at the till
In many places the shelf price excludes tax, so the amount paid exceeds the marked price. Computing the total means multiplying by one plus the tax rate, which is a percentage increase.
Calculating a tip mentally
10% is the bill with the digits shifted one place. Half of that is 5%. So 15% is 10% plus 5%, and 20% is double 10%. Building from 10% is fast and needs no device.
Tip on the pre-tax amount
Conventionally the tip is calculated on the bill before tax, though many people use the total. The difference is small on a small bill and worth knowing on a large one.
Rates vary by place and item
Sales tax rates differ between jurisdictions and some goods are exempt or reduced. There is no single rate to memorise, only the method for applying whichever rate applies.
Step 2: Try It Yourself
Tap and try it out.
Item
Tax
Tip
Item has the most. It has 46 more than Tax.
Step 3: Watch an Example
One step at a time.
Watch Ines Total a Meal
A $60 meal with 8% tax and an 18% tip on the pre-tax amount.
- Step 1
The tax is 0.08 × 60 = $4.80.
Step 4: Your Turn
Practice makes it stick.
The Register
Problem 1 of 2
A $50 item with 8% sales tax. Total in dollars?
dollars
The Tip
Problem 2 of 2
A $40 bill with a 20% tip. Tip amount in dollars?
dollars
Add It Up
1 of 8
A $200 item with 5% tax. Total in dollars?
2 of 8
A $80 bill with a 15% tip. Tip in dollars?
3 of 8
A $54 total at 8% tax. Pre-tax price in dollars?
4 of 8
A $60 meal, 8% tax and 18% tip. Total in dollars?
5 of 8
10% of $73, to two decimal places?
6 of 8
A $25 item with 4% tax. Total in dollars?
7 of 8
To recover a pre-tax price from a total, what should you do?
8 of 8
A $110 total at 10% tax. Pre-tax price in dollars?
Step 5: Quick Check
Show what you know.
Question 1 of 2
A $150 item with 6% tax. Total in dollars?
Question 2 of 2
Why does subtracting 8% from a total not recover the pre-tax price?
What You Learned
- Sales tax is added at the register; multiply by 1 plus the rate.
- Tips are computed on the pre-tax bill.
- To undo a tax, divide by 1 plus the rate rather than subtracting.