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Wednesday, December 18, 2013

Ceci's Percent Post



Percent means...
Percent s a equivalent fraction that's out of 100.
They picked 100 to be percent because 100 is the right number that's not too big and not too small.
the word percent and symbol % both meant out of 100, PER = out of, and CENT = 100. % = /100.

Here is how we find %,
we can use a T chart to find the %,
for example,
 we have 60 pencils,
what is 10% of 60?
what is 25 % of 60?
what is 50 % of 60?


                          PERCENT  |    PENCILS
                          100      |     60
               /10                 |                /10
                          10       |     6



                         PERCENT   |    PENCIL

                          100      |     60

              /4                   |                /4
                          25       |     15



                        PERCENT   |    PENCIL

                          100     |     60
             /2                   |                /2
                          50      |     30


Representing Percent


a)180%

















b)0.6%



                                        
                                      













c) 12 3/8      








Converting percents


fraction -- decimal -- percent
88/50
88/50 = 1.76
because 88 divide by 50 equals = 1.76,
1.76/1 * 100/100 = 176/100 or 176%


decimal -- percent -- fraction
0.0064 * 100 = 0.64 or .64%
0.0064 = 64 /10 000


 64        16       4
---   /   ----  =  ---
10000      16      625





percent -- decimal -- fraction
0.3%
0.3 / 100 = 0.003
0.003 = 0.003 / 1000
0.003 = 3 / 1000



understanding percent,

combining percents,

decimal, fraction 

4.

1) 20% of 60
   10% = 6
   because, you move the decimal  60. to the left once,
   10 x 2=20
   6 x 2=12

   calculation:
   20/100
   0.20 x 60 = 12

2)0.1% of 40
   0.1 x 1000 =100
   40/1000 = 0.04

   calculation:
   0.001 x 40 = 0.04

3)250% of 400
   250 x 400 = 100000
   100000 / 100 = 1000
 
   calculation:
   250/100 = 2.5
   400 x 2.5 = 1000

 



5.
Tips: % OFF = discount,what you save
 sale price = what you pay  

question 7 from pg. 149 (text book)
 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.
 


first year:
10 + 100 = 110
110     100     1.1
---  /  ---  =  ---  =  1.1
100     100      1

1.1 X 100 = 110

     OR

10% of 10010% + 100% = 110%
110/100 = 1.1
1.1 x 100 = 110







second year:
110 caribou
20 + 100 = 120
120   100    1.2
--- / ---  = --- = 1.2
100   100     1

1.2 X 110 = 132

   OR

20% of 110
20% + 100% = 120 %
120 / 100 = 1.2
1.2 x 110 = 132

The population after the second year is 132.


b) Explain why there was not a 30% increase in population over the two years.

 There was not a 30% increase in population over
 two years because, the percent had changed. we
 need to find 10% of 100 first, when we get the
 answer we have to  find 20% of that number.The
 number had changed, we are not looking for the
 percent of 100 so, the final answer would
 change too.




 SHOW YOU KNOW ....

What is the final sale price at each store? Which is a better buy?
Explain your thinking.

Store A: 50% off one day only

Store B: 25% off one day followed by 25% off the reduced price the

second day




For Example
The total price of the jacket is 200 dollars

store a)





50% off means half off
half of $200 is $100

    OR 

50% = 0.5
0.5 X 200 = $100







store b)

the first day...



75% = 0.75
0.75 X 200 = $150

    OR 

25% of 200 = 50
200 - 50 =$150









the second day...




75% = 0.75
0.75 X 150 = $112.5

     OR 

25% of 150 = 37.5
150 - 37.5 = $112.5





The final price for store a) is $100, and for sore b) is $112.5. Store a) is a better choice because, store a) is 50% off which means it is half of the regular price. Store b) is 25% off from the regular price, and 25% off from the reduced price, the number had changed smaller so, the discount would change smaller too. If the discount  gets less then, the sale price gets more.





 convert percents, decimals and fractions....





























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