Robson's Percent Post

*Percent means out of 100, it is an equivalent fraction that is out of 100.

*Here is how we find-
  10 out of a hundred-10/100-All you have to do is divide 100 by 10.
  Half Of 100 50/100-You divide 100 by 2 because 50 is half of 100
  Quarter of 100-25/100-Divide 100 by 4 because 4 25's is 100 so you do the opposite
  One out of a hundred-1/100-You divide 100 by 100 because if you divide any number by itself you will get 1.

*Percent is Latin for percentum or per 100. We can also use French, Per=out of and cent=100.
*Why percents revolve around 100 is a very hot topic, my genius has helped in figuring it out. We use 100 because it is a friendly number and is and easy number to use better than using the number 69.
*You can also go above the 100/100 barrier by doing something like 205/100. This form of fraction is called top heavy or an improper fraction. For every 100 in 205 it will equal to 1 whole making this 2 wholes and 5 hundredths.
*You may see 100 in % because there are zeros on both sides of the fraction line and the fraction line somehow represents 1.
*We can use simple things for fractions we can use apples.
40 Apples  100 Percentage               What you do on one side you have to do to the other.    
40/4=100     100/4=25
40/10=4       100/10=10
40/100=0.4  100/100=1
40/1=40       100/1=100

2. *180%-

   *12 3/4% - 

  *0.7%- 

 

Converting Fractions,Percents and Decimals

Converting fractions to percent and decimals


5/40
To turn this fraction into a decimal you have to divide the numerator by the denominator.
ex. 5÷40=0.125
To turn this decimal into a percent you have to multiply the decimal by 100.
ex.0.125 x 100 = 1.25
Now you must be confused by my amazing math. This is how I did it.
0.125 over 1. 0.125 x 100 now what you do to the numerator you do with the denominator so
0.125 x 100 now since 0.125/1 you have to multiply the 1 by 100 so 100.
now its 12.5 over 100 12.5/100.

Converting decimals to fractions and percents

0.070
To turn this decimal into a fraction you have to figure out which place value this number i in.
ex. 0.070/1000
Now you have to multiply the numerator by the digits of the numerator.
ex. 0.070 x 1000= 70
This forces the decimal into a "regular number".Now you have to divide this number by 2 and do the same for the denominator.
ex. 70÷2=35/1000÷2=500
You cant go any further because you cant divide 35 by 2 and get an even number.
To turn fractions into percents you have to divide your numerator by your denominator.
ex. 35÷500=0.07 
Now you have to multiply this number by 100.
ex. 0.07 x 100 = 7%

Converting percents to decimals and fractions

40%
To turn this percent into a decimal you have to divide your percent by 100
ex. 40÷100= 0.4
Now to turn this decimal into a fraction.
You have to multiply the decimal by 100.
ex. 0.4 x 100 =40/ 100
40/100

Percent of a Number

*Percent of a number is the next part of this exercise. Show how you could solve the following using mental math and a calculator

*20% of 60 - 20% ÷ 100 = 0.2 x 60 =12

*0.1% of 40 - 0.1% ÷ 100 x 40 = 0.001 =0.04

*250% of 400 - 250% ÷ 100 = 2.5 x 400 =1,000

Combining Percent

*Combining Percents is the last part of this post. You need to explain Discount, Sale price and Total Price with taxes. I also need  you to explain what is better deal 50% off or 25% off of an already reduced price of 25% This can be done using the following Questions,

No 25% and 25% combined are not the same as 50%. This is not the same because if you calculate 25 divided by 100 then multiply by the price. ex. 25 ÷ 100 x 150 =$37.50 - 150 = 112.5

Now it's a reduced price you have to drop the price by 25 again 25 ÷ 100 x 112.5 = $29.25 - $112.50=  $83.25

50% of 150 - 50% ÷ 100 x 150 =$75.00

$75.00 < $83.25

$75.00 is a better deal because it costs less than $83.25

*0.6%

                             








*12.3/8

Pam's Percent Post

Notes:

• Percent means/is an equivalent fraction that is out of 100.

ex. 9/10 x 10/10 = 90/100 or 90%.

• Percent is out of 100 because "It's just right" and it's "easily seen", and it could also be a friendly number.
• The percent symbol (%) includes two zeros and the division sign. The division sign is the 1__ and the two zeros are _00 making it 100.
• In French, the word percent is split into two parts, "per" being "out of" and "cent" being "100".
• You may be asked, is 205% still a percent? even though it's past 100? It still can be. It's 205/100.
• Percent can be an "improper fraction" meaning that the numerator is greater than the denominator in a fraction. Another word for this could be "Top Heavy". ex. 5/4

100%- means all, whole, everything.

50% - means half, part/whole, 20/40 or 50/100

   %    |  apples
  100  |   40
    50  |   20
*We divided both sides by 2.

10% - is 10/100

   %    |  apples
  100  |   40
   10   |    4

25% means 25/100 or 1/4
 
   %    | apples   
 100   |    40
   25   |    10
*We divided both sides by 4.

1% - means 1 out of 100 or 1/100
*To find 1% of something, divide the number by 100.

   %    | apples
   100 | 40
     1   | 0.4
*We divided by 100 on both sides (what you do to one side, to do to the other).

Representing Percent

180 %







____________________________________________________________________________

0.6%

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    12 3/8 %

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FRACTION - DECIMAL - PERCENT

3/40   Numerator ÷ Denominator = Decimal
                           3 ÷ 40 = 0.0.75  x 100   =   7.5  or 7.5%
                                            1     x 100        100
_____________________________________________________________________________________               

DECIMAL - PERCENT - FRACTION

0.0064    0.0064  x 100      0.64  or 0.64%    →    0.0064
                   1       x  100     100                             10000

_________________________________________________________________________

PERCENT - DECIMAL - FRACTION

0.3% ÷ 100  =  0.003  →   3     
                                         1000

_________________________________________________________________________

                                                PERCENT OF A NUMBER

MENTAL MATH                                                                     CALCULATOR

20% of 60 -             %  |  #                                                    20   20 ÷ 100 = 0.2
                             100  | 60                                                  100
                (÷ 5)       20  | 12                                                
                                                                                             0.2 x 60 = 12

* 0.2 is 20% and you must find the decimal of 

the percent by dividing the percent by 100.

                                                                                                                                                        

0.1% of 40  -          %   |  #                                                  0.1     0.1 ÷ 100 = 0.001
                              100 | 40                                                100
              (÷ 1000)   0.1 | 0.04
                                                                                            0.001 x 40 = 0.04
* when dividing 10, 100, 1000, etc, you
move the decimal place by how much zeros
there are in the number you are dividing by.
When there is no decimal, the decimal is always
on the right side of the ones place value.
     
                                                                                                                                                        
250% of 400 -        %  |  #                                                  250           250 ÷ 100 = 2.5
                             100 | 400                                               100
                     (x2)  200 | 800
       (÷ 2 from 100)    50 |  200                                              2.5 x 400 = 1000

800 + 200 = 1000

                           
___________________________________________________________________________

5.                                                 COMBINING PERCENT                                                     

Question 7 -page 149                                                            

                                                                                             

A herd of 100 caribou was moved to a new 

location. The population increased by 10%

the first year and then increased by 20% the

second year.

a) Find the population after the second 

year.

b) Explain why there was not a 30% increase

in population over the two years.

__________________________________________________________________________

WORK :

first year

                  - The caribou population (the whole or 100%) was increased by 10%, meaning that 10% was added to the whole, so you could just find 110%.

   

            100%         - caribou

            + 10%        -increase in population

            110%

             110            110 ÷ 100 = 1.10
             100                                            1.10 x 100 = 110

    second year

- This is now the new percent since you are trying to find

a percent of a percent. You try to find 20% of 110 caribou

instead of the original 100 caribou. The 20% must be added into

the 100% (110 caribou)

or only use one step:

             100%             120 ÷ 100 = 1.20    1.20 x 110 = 132

            + 20%                                    1

             120%               On the second year, there were 132 caribou.

explanation

There was not a 30% increase over the years because if it was

30% increase, it would of been 130 caribou. This was not the same

and we did not get the same answer as a 30% increase because in the process

of finding 20% of 110 caribou and adding the 20%, we also had a new 100% or

a new all. This is finding a percent of a percent.

__________________________________________________________________________

Show You Know pg. 148

What is the final sale price at each store? Which is a better buy?

Explain your thinking.

Store A : 50% one day only

Store B : 25% off one day followed

by 25% off the reduced price the

second day

example price for both BAGS : $50

Store A

for one day:

50% off (discount ) of $50.

Since this is the discount, the discount is what you save, while the sale price is what

you pay. You could just find the sale price but since this is 50%,

you could just half the number at this point.

50÷2 = 25

$25 is the reduced price, or the amount you are now paying (not including taxes).

Store B

first day:
25% off of $50

 25       25 ÷ 100 = 0.25
100

0.25 x 50 = $12.50

Since this price is the discount, we try to find the sale price. The
sale price is 75% (subtracting 25 off of 100).
Then we subtract $12.50 from $50 = $37.50
You pay $37.50.

* You could have just found 75% of $50 rather than finding 25%
then subtracting that number from the regular price.

second day:
25% off of $37.50 (new 100%)

 25      25 ÷ 100 = 0.25
100

0.25 x 37.50 = $9.38

$37.50 - $9.38 = $28.12

conclusion

In conclusion to this math problem, store a would have been the better buy.

Store A is offering $25 for a bag while Store B is offering $28.12 on the second day.

If you choose Store A over Store B, you'll save $3.12 compared to Store B's price.

Again, for Store B, it's different from Store A because Store B includes you to find

a percent of a percent meaning there will be a new 100%.

 Overall, Store A has a better buy.

_________________________________________________________________________