Corinne's Percent Post

"Welcome to my percent post."

Part 1 - Finding Percents

• 50%

To get 50%, you take the whole then divide by 2.
eg. 50% of 80 = 40 ( 80 / 2 = 40)

• 10%

To get 10%, you take the whole then divide by 10.
eg. 10% of 20 = 20( 20 / 10 = 2)

• 1% 

To get 1%, you take the whole and then divide by 100.
eg. 1% of 11 =0.11 ( 11 / 100 = 0.11)

• 25% 

To get 25%, you take the whole then divide by 4.
eg. 25% of 40 = 10( 40 / 4 = 10)

Percent - A percent means out of 100, and is another way of saying hundredths.

Part 2 - Representing Percents

• 180%

This is a representation of 180% on a hundred grid.

• 12 3/4% 

This is a representation of 12 3/4% on a hundred grid.

• 0.7%

This is a representation of 0.7% on a hundred grid.

Part 3 - Converting Decimals, Percents, and Fractions

• 26% 

- Decimal - To convert a percent into a decimal, you take the whole, then you divide by a hundred.

eg. 26 / 100 = 0.26

- Fraction - To convert a percent into a fraction, first you have to, get the percents' decimal number, and the digits becomes the numerator. Then you look to see what place value the last digit is in. The place value of the last digit becomes the denominator in your fraction.

eg. 26 / 100 = 0.26 - the last digit (6) is in the hundredths place value
26/100

• 7/10

- Decimal - To convert a fraction into a decimal, you take the numerator and you divide it by the denominator.

eg. 7 / 10 = 0.7

- Percent - To convert a fraction into a percent, you first have to get the fractions decimal, then you multiply the decimal by 100.

eg. 7 / 10 = 0.7

0.7 x 100 = 70%

• 0.024

- Percent - To convert a decimal into a percent, you have to multiply the whole by 100.

eg. 0.024 x 100 = 2.4%

- Fraction - To convert a decimal into a fraction, you take the digits and make it the numerator. Then you look to see what place value the last digit is in. The place value of your last digit will be your denominator.

eg. 0.024 - the last digit (4) is in the thousandths place value.

24/1000


Part 4 - Percents of a Number

• 20% of 60

Mental Math - To find 20% of 60 using mental math, you figure out 10 percent of 60 is, then you multiply that number by two (20%)!
eg. 10% of 60 = 6
10% of 60 = 6
6 + 6 = 12

Calculator - To find 20% of 60 using a calculator, you take the whole, and divide it by a 100, and you will get an answer of a decimal number. Next you take that decimal number and you multiply it by 20.
eg. 60 / 100 = 0.6
0.6 x 20 = 12

• 0.1% of 40

Mental Math - To find 0.1% of 40 using mental math, you have to figure out what 1% of 40 is, then you take your answer and divide that by 10, which is 0.1%. Also, if you know that to get 1% of a number, you divide by 100, then that means to get 0.1% of a number, you divide by 1000.

-eg. #1 - 1% of 40 = 4

(1% / 10 = 0.1%) 

4/ 10  = 0.04

-eg. #2 - 40 / 1000 = 0.04 (0.1%)

Which is like saying : (40 / 100 / 10 = 0.04)

Calculator - To find 0.1% of 40 using a calculator, you take the whole, and divide it by 100, and you will get an answer of a decimal number. Next you take that decimal number and multiply it by 0.1.

eg. 40 / 100 = 0.4

0.4 x 0.1 = 0.04

• 250% of 400

Mental Math - To find 250% of 400 using mental math, you take the whole, and you multiply it by two (200%). Then next, you divide the whole to get 50%.

eg. 400 x 2 = 800

(400 / 2 = 200)

200 + 800 = 1000 

Calculator - To find 250% of 400 using a calculator, you take the whole and divide it by 100, and you multiply your answer by 250(%).

eg. 400 / 100 = 4

4 x 250 = 1000

Part 5 - Combining Percents

Discount - A discount is when a price is deducted (reduced, took away) from its original value.A discount is a percentage of the whole, and that percentage is the money you save.

Sale Price - A sale price is a lower price that is reduced from to help you save money. The money that you save from a sale, is the discount!  

Total Price with Taxes - A total price with taxes is the final price of an item that you pay extra for, depending on where you live; the extra money goes to your government and your province (PST - Provincial Sales Taxes, and GST - Government Sales Taxes)

Question :

Store A: $240.99 (50% off one day only)

Store B: $231.00 (25% off one day, followed by 25% off the reduced price the next day)

Store A: $240.99 / 100 = 2.4099
2.4099 x 50 = 120.495 ($120.50)
$240.99 - $120.50 = $120.49

Store B: $231.00 / 100 = 2.31
2.31 x 25 = 57.75
$231.00 - $57.75 = $173.25
$173.25 / 100 = 1.7325
1.7325 x 25 = 43.3125 (43.31)
$173.25 - $43.31 = 129.9375 ($129.94)

Store A is a better buy because you save more money (save - $9.45).

• A better deal would be taking 50% off an original price, because taking 50% off is pretty much dividing the price in half. But when you take an original price and deduct 25% and then another on the deducted price, you take 25% off on an even smaller number, meaning your answer will be a smaller amount.

That is my percent post!