#### 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**

3) Add $32.50 and $65.00

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

Buy it! Call and text your friends about the great sale.

**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 another 10% ---> $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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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**

3) Add $32.50 and $65.00

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

Buy it! Call and text your friends about the great sale.

**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 another 10% ---> $13.00

Add 5% by taking half of $13.00 ---- 6.50

Thus $13.00 + $13.00 + $6.50 = $32.50

See Free and Budget-friendly Math Books

Beverlymackie.net

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