#### Percents - Mentally Calculate Discount Retailers advertise big sales and deep discounts to lure you into their stores. Once you enter the stores and see 20%, 25 %, 60%, and even 75% off, adrenaline begins to flow as you shop for bargains. You find the perfect gift or bargain. Then, you wonder how much will I save? How much should I expect to pay at the register?

Generally, you do not have a calculator or pencil and paper in your hand. So, let’s look at a few ways to mentally calculate the discount and sale price.

First example: 20% off of \$14.99 game
What is the discount or amount saved?

1) Round \$14.99 to the nearest dollar --- \$15.00
2) Calculate 10% of \$15.00 by moving the decimal to the left once --- \$1.50
3) Then double \$1.50 to get 20% --- \$3.00 discount or amount saved.

You will save \$3.00.
4) To determine the approximate sale price – subtract the savings from the original price
\$15.00 - \$3.00 = \$12.00

Second example: 25% off of \$35.00 pants
What is the discount or amount saved?

1) Calculate 10% of \$35.00 by moving the decimal to the left once --- \$3.50
2) Then double \$3.50 to get 20% --- \$7.00
3) To calculate an additional 5%, take ½ of 3.5 --- \$1.75 **see note
4) Add \$7 and \$1.75 --- \$8.75 or round to \$9.00 discount or amount saved.

You save ~ \$9.00.
5) To determine the approximate sale price – subtract the savings from the original price
\$35.00 - \$9.00 = \$26.00 approximate sale price

**If taking half of \$3.50 is confusing, then round \$3.50 to the nearest dollar. --- \$4.00.
Take ½ of \$4.00 ---\$2.00 this is ~ 5% of \$35.00
Add \$2 and \$7 --- \$9.00 savings

Third example: 60% off of \$80.00
What is the discount or amount saved?

Calculate 10% of \$80.00 by moving the decimal to the left once --- \$8.00 Then, think
10% --- \$8.00
10% --- \$8.00
10% --- \$8.00
10% --- \$8.00
10% --- \$8.00
10% --- \$8.00
------------------------
60% --- \$48.00

In short, 10% of \$80.00 is \$8.00, therefore mentally multiply \$8.00 times 6 to get \$48.00 discount. Round to the nearest dollar --- \$50.00

You save ~ \$50.00.
To determine the approximate sale price – subtract the savings from the original price
\$80.00 – \$50.00 = \$30.00 Buy it!

Fourth example: 75% off \$130.00
What is the discount or amount saved?

1) Calculate 50% or half of \$130.00 --- \$65.00
2) Next determine 25% of \$130.00 --- \$32.50**

Total discount or amount saved is 97.50 or ~ \$100.00
4) To determine the approximate sale price – subtract the savings from the original price
\$130.00 – \$100.00 = \$30.00 approximately

**How does 25% of \$130 equal \$32.50?
Since, 50% or half of \$130.00 --- \$65.00 and 25% is half of 50%
Then 25% is half of \$65.00 which is 32.50

or

Mentally calculate 10% of \$130.00 by moving the decimal to the left once ---- \$13.00
Add 5% by taking half of \$13.00 ---- 6.50
Thus \$13.00 + \$13.00 + \$6.50 = \$32.50

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