## Tuesday, December 17, 2013

### Heather's Percent Post

A Percent is an equivalent fraction out of 100. Percents are related to fractions. To get the percent in a fraction form you divide the numerator with the denominator and it will give you a decimal. You then multiply the decimal by 100, and it will give you a number out of 100.

N/D = Decimal/1
Decimal x 100 = ?/100

100 percent means everything (e.g 100/100 or 16/16). Per Meaning out of and cent meaning 100, so a percent means a number out of 100.
To find 100 percent, you divide the number  by 1,  and it will give you 100% of that number.
example: 100% of 40 = ?
40/1 = 40
100% of 40 is 40
50 percent means half or 1/2 or 50/100.
To find 50 percent, you divide the number by 2, and it will give you 50% of that number.
example: 50% of 40 = ?
40/2 = 20
50% of 40 = 20
10% means 1/10 or 10/100.
To find 10 percent, you divide the number by 10, and it will give you 10 % of that number.
example: 10% of 40 = ?
40/10 = 4
10% of 40 = 4
25 percent means 1/4 or 25/100.
To find 25 percent, you divide the number by 4, and it will give you 25% of that number.
example: 25% of 40 = ?
40/4 = 10
25% of 40 = 10
1 percent means 1/100.
To find 1 percent, you divide the number by 100, and it will give you 1% of that number.
example: 1% of 40 = ?
40/100 = 0.40
1% of 40 = 0.40

Representing Percents

180%                                                            12.3/4%

0.6%

Converting Fractions to Decimals and Percents: 88/50
Numerator divide by the Denominator
88 divide by 50 = 1.76
1.76 x 100 = 176%

Converting Decimals to Percents and Fractions: 0.0064
0.0064/1 x 100/100 = 0.64/100 or 0.64%
64/10000 divide by 16/16 = 4/625

Converting Percents to Decimals and Fractions: 750%
750 divide 100 = 7.5
750/100 = 7.5 or 7 1/2

Show How You Know: (Mental Math)
20% of 60:      60 ÷ 10 = 6
6 x 2 = 12
20% of 60 is 12

0.1% of 40:      40 ÷ 100 = 0.4
0.4 ÷ 10 = 0.04
0.1% of 40 is 0.04

250% of 400:   400 = 100%
400 ÷ 2 = 200 (50%)
200 x 5 = 1000
250% of 400 = 1000

Calculator:

20% of 60 :                               0.1% of 40:                           250% of 400
20÷100=0.2                                 0.1÷100=0.001                         250÷100=2.5
0.2 x 60=12                                0.001 x 40=0.04                     2.5 x 400=1000
20% of 60 is 12                          0.1% of 40 is 0.04                     250% of 400 is 1000

Question #3 on pg 148:

a) 15 ÷ 100 = 0.15       b) 10 ÷ 100 = 0.1          c) 25 ÷ 100 = 0.25
0.15 x 200 = 30            0.1 x 230 = 23             0.25 x 200 = 50
30 + 200 = 230             23 + 230 = 253            50 + 200 = 250

Kyle is incorrect.

Discount - what you save
Sale Price - what you pay
Total Price - what you pay altogether with tax.
( Discount - Original Price = Sale Price)     (Sale Price + Tax = Total Price)

Show How You Know pg 148
Which is a better buy? What is the final price?
Plate Collection \$ 68.00
Store A: 50% off one day only
68 ÷ 2 = \$34

Store B: 25% off one day followed by 25% off the reduced price the second day.
25 ÷ 100 = 0.25               \$51 x 0.25 = \$12.75
0.25 x 68 = \$17               \$51 - \$ 12.75 = \$38.25
\$68 - \$17 = \$51

Store A has a better deal because it is less than Store B after the discount.