1. Yes, you can do it! Mind Calculation: Percent By Kitty Huang

2. Objectives  To empower students by using a real life math application that is interesting and useful to them.  Students can do mind calculation with the knowledge of the simple multiplication table.

3. Question  How do you know if a discounted item is worth buying? We don’t bring calculators to the stores, do we?

4. On Sale  A T-Shirt is $30 originally  The store offers a holiday discount of 40% off.  What is the sale price?

5. The equation  $30 dollars with 40% discount.  If the discount is 40% off, then we pay 60%.  So the equation is: $30 x 60%=the sale price

6. Write the equation in fraction form  $30 x 60% = The sale price

7. Zeros cancel out

8. Focus on the first digit

9. Review  Mentally remember the 3 in $30 dollars.  Show all 10 fingers.  If the discount is 40% off, then lower 4 fingers.  There are 6 fingers remain.  Multiply 3 and 6.  The answer is 18.

10. Exercise  A textbook is $80.  The new beginning discount is 40% off.  How much is the sale price?

11. Solution  A textbook is $80.  The discount is 40% off. (10-4=6)  So the sale price is: 8 x 6 = 48

12. Yes! You Did it! Q & A