2. Why??  Percents are all around us! Sales and discounts shopping Sales Tax Income Taxes Tips on restaurant bills Etc…  When doing problems with % remember all %’s can become decimals!

3. The How!  Convert all percentages to decimals i.e. 85% = 0.85150% = 1.50  Multiply the original cost of an item by the percentage to find the cost of the increase or decrease  Add (taxes, markup, etc) or Subtract (sale, discount, etc) by the amount to find the final price.

4. Example #1  The original cost of a sweater is $32.00. What is the price after a 20% discount? 20% = 0.20 32.00 * 0.20 = 6.40 $32.00 - $6.40 = $25.60

5. Example #2  A $20,000 car is on sale for 15% off. What is the sale price of the car? 15% = 0.15 20,000 * 0.15 = 3,000 20,000 – 3,000 = $17,000

6. Example #3  You and your friends go to Applebee’s for dinner and spend $45.23. If you leave a 18% tip, what is your total cost? 18% = 0.18 45.23 * 0.18 = 8.14 45.23 + 8.14 = $53.37

7. Example #4  There is a 7.5% sales tax on a $240 TV. How much should you pay? 7.5% = 0.075 240 * 0.075 = 18 240 + 18 = $258

8. Example #5  Best Buy has a $199 phone on sale for 15% off. Then you have to pay 7% sales tax. How much will it cost? 15% = 0.15199* 0.15 = 29.85 199 – 29.85 = $169.15 7% = 0.07 169.15 * 0.07 = 11.84 169.15 + 11.85 = 180.99

9. Example #6  A $550 computer is on sale for 25% off. How much will the computer cost after a 8.5% sales tax? 25% = 0.25550 * 0.25 = 137.50 550 – 137.50 = 412.50 8.5% = 0.085412.50 * 0.085 = 35.06 412.50 + 35.06 = $447.56