## Tuesday, December 17, 2013

### Gabby's Percent Post

What is a percent?
A percent is a fraction out of 100 that we see almost everywhere without even thinking about it. Store sales have percents that you may think is a good deal but turns out to be more than you know.
Why is "%" the symbol for percent?
The symbol "%" actually means "out of 100". The two circles stand for a zero while the line is a 1. This explains why the percentage sign is stood out like that. French people decided to have 100 as the percent number because its not too little like 10 and not too big like 1000, it's just
right.

A numerator and a denominator?!
A fraction is something that can make finding the percentage of a number 10x easier because the denominator is basically telling you what the 100% is. The numerator is than telling you how much of 100% you are using. ex 50/100= 50%. The denominator of a decimal is always 1 while the denominator of any other whole is 100.

What is 100%?
100% means everything. An example of this is 40/40=100/100. 100% is the whole number.

How do you get the percentage of 50 out of 100?
If you want to get 50% out of 100 you can divide 100 by two. You can divide any number into two and get its 50%. An example of 50%: (This is why 100% is better :D)

How do you get the percentage of 25 out of 100?
To get the percentage of 25 out of 100 you must divide 100 by 4. Even with a different whole number you may still divide the number by 4 and get the 25% of that particular number. ex: 100/4= 25, 200/4= 50.

How do you get the percentage of 10 out of 100?
You can get the percentage of 10 by dividing the denominator and the numerator by 10,and than moving the decimal into the place value that its supposed to go to determined by how much was divided if a decimal is needed. ex. 100/10=10

How do you get the percentage of 1 out of 100?
To get the percentage of 1 out of 100 you have to divide 100 by itself,If the denominator is not 100 than you must divide by 100 anyways. ex: 100/100=1, 50/100= 0.5.

How do you find the percentage of a "ugly" number out of 100?
If you have found what 1% is out of 100 you can determine any number by multiplying it by the "ugly number". ex: 1% of 100= 1x37=37. 37% out of 100 is 37.

Representing Percent:
Percents can also have fractions of 1 single square (ex.0.6) and percents more than 100 (180).
If you have a percent that is a fraction in one single square. You have to show it by making it larger.
Sales and Percents: Daily life

In our daily lives we have percents but never really think about them. The usual spots where we see percents are mall sales. Some people just think "WOW! ITS A SALE" and think it's very cheap but no! Some sale prices are actually raised up to a bigger price than before, making no difference or very little.

Decimals and Percents
All decimals can be turned into a percent by multiplying by 100. All decimal numbers have the denominator of 1 while everything higher and a whole, has the denominator of 100.

If you have a percent larger than 100, you use another grid.
180%, 180 out of 100, or 1.80 out of 1

Microscopic maximization numbers

0.6%, o.6 out of 100 or 0.6/100

Mixed fractions on 100 grid
12 and 3/4 %, 12 3/4 out of 100, or 0.12.75

Converting Percents Fraction and Decimals.

Fraction -> Decimal -> Percent
Question: 3/40
Answer: 3 divided by 40=0.075 (decimal) 0.075x100= 7.5% (percent)

Decimal -> percent -> fraction
Question: 0.0064
Answer: 0.0064x100= 0.64% (percent) 0.64% find the place value.In this case it is 0.64/100

Percent->decimal-> fraction
Question: 750%
Answer: 750% divided by 100= 7.5 to find the fraction you have to say the number. In this case it's is 7 and a half because .5 is half of a whole number. 7 1/2

Representing Percents:

Percent ->decimal-> fraction

• 26%
26/100 (26 divided by 100)= 0.26 . To find the fraction all you have to do is say the number out loud. 26/100.
Fraction ->decimal->percent
• 7/10
7/10 (7 divided by 10)= 0.7 . 0.7x100= 70%

Decimal ->percent -> fraction
• 0.024
0.024x100=2.4, find the place value and set it up; 2.4/1000\

Converting how much a percent is:

• 20% of 60=12
•
Calculator:
To find 20% of 60 you have to turn 20 into a decimal. You divide 20 by 100 (20/100) and get a decimal ( 0.2). 0.2x60=12.
Mental Math:

• 0.1% of 40

• Calculator:
0.1/100=0.001  . 0.001x40= 0.04
Mental Math: I have made a t-chart

• 250% of 400

•  Calculator:
250/100 (250 divided by 100)=2.5 . 2.5X250= 625
Mental Math:

Because 250 divided by 100 is 2.5, if you multiply that by 100 you will get 250. What you do on one side will be done to the other due to equivalent balance.

Question 5 (Sargent Park Math Zone):
You have to find 90% because it is easier. To find 90% you have to divide 90 by 100 and than multiply the number you get also by 100 because it is the number of caribous that we are talking about in year 1.

90 divided by 100 is 0.9
After you get 0.9 you multiply it by 100 which is 90. 90-100=10. This means 10% is 10.

Than you do the same thing with the 20. You find 80 and divide 80 by 100. After you get 0.8 you multiply it by 100 getting 80. 80-100= 20. This means 20% is 20.

Question 5 Show you know (Sargent Park Math Blog):

Store A: 50% off only 1 day

Store B: 25% but followed by another 25% the next upcoming day.

If store A has a sale of 50%  the price would be 100.

If store B is having a sale for 25% . 25% of 200 is 50 because 200 divided by 4 is 50. This means that 25% is 50. 50-200= 150. The next day they had another sale in the store for 255 again. 150 divided by 4 would equal to 37.5.  150-37.5- = 112.5