Find the tax amount and total cost of any purchase
How Sales Tax Works
Sales tax is a percentage added on top of a purchase price. The rate varies by state and city.
To find the tax amount: multiply the price by the tax rate (as a decimal).
To find the total cost: add the tax to the original price.
Instead of calculating tax and adding it, multiply by (1 + tax rate).
With 8% tax: $50 × 1.08 = $54.00. Same answer, one step.
This works because you're paying 100% of the price plus 8% tax = 108% total = 1.08.
💡 Mental math for sales tax: Find 10% of the price (move decimal left), then adjust. For 8% tax, find 10% and subtract 2% (which is 1/5 of 10%). Close enough for quick estimates at the store.
🎯 Practice Problems
1. An item costs $25. Sales tax is 6%. What is the tax amount?
A) $0.15
B) $1.50
C) $6.00
D) $2.50
2. A $100 purchase has 7% tax. What is the total cost?
A) $170
B) $107
C) $700
D) $100.07
3. A $40 item has 8.5% sales tax. What is the tax amount?
A) $3.40
B) $34.00
C) $4.00
D) $8.50
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🎯 Bonus Practice
1. You buy a $200 TV with 6% tax. What do you pay in total?
A) $206
B) $260
C) $212
D) $220
2. An item costs $75 with 10% tax. What is the total?
A) $85
B) $82.50
C) $750
D) $7.50
3. You paid $53.50 total for a $50 item. What was the tax rate?
A) 3.5%
B) 5%
C) 7%
D) 10%
4. A $15.99 meal has 8% tax. Approximately how much tax?
A) $0.80
B) $1.28
C) $8.00
D) $12.80
5. To find the total cost in one step with 9% tax, multiply the price by…