Nassia's Percents Post

Hi, this is my percents post! -Nassia


1) Key Percents:

- To find 50% of a number, divide it by 2.
- To find 10% of a number, divide it by 10.
- To find 1% of a number, divide it by 100.
- To find 25% of a number, divide it by 4.

A percent is... a number out of 100. When you break the word percent up, you get "per" and "cent, which means "per one hundred" basically.

 2) Represnting Percents

a) 180%
      
b) 12 3/4%














c) 0.7   .....???

3) Converting Decimals, Fractions, and Percents


26% -------->    26÷100= 0.26 (Decimal)
                           26/100 (Fraction)

EXPLANATION: To convert 26% into a decimal, you divide it by 100, and you get 0.26, your decimal number. To convert that into a fraction you first take 0.26, and since there are NO decimals in a fraction, you just exclude it. The same goes for the zero at the front because it has no value. Now you have 26. That will become the numerator of your decimal. To find the denominator, you look at the decimal number you found, and find the place value. The place value of 0.26 is 100. When you peice your fraction together, you get 26/100!! TA-DA!

7/10 -------->  7÷10= 0.7 (Decimal)
                         0.7X100= 70% (Percentage)

EXPLANATION: To convert 7/10 into a decimal, you divide the numerator (7) by the denominator (10). From that you get the decimal number, which is 0.7. To get the percentage, you multply the decimal you just got by 100, and you get the answer 70%.


0.024 -------> 0.024X100= 2.4% (Percentage)
                        24/10 (Fraction)

EXPLANATION: To convert 0.024 into a percentage, you have to take it and multiply it by 100. After you get your answer from that, use it to get the fraction. There are no decimals in fractions, so 2.4 turns into 24, and the place value of the decimal is 10. You get 24/10.


4) Percent of a Number ( Calulator and No Caculator)

20% of 60 ------> CALCULATOR: 0.20 X 60 = 12
                              NONE: 10% of 60 = 6           6 X 2=12


0.1% of 40 ------> CALCULATOR: 0.1x40=4
                               NONE: 0.1% is 4


250% of 400 ------> CALCULATOR: 250÷100= 2.5      2.5x400= 1,000
                                  NONE: 100% of 400 = 400
                                               100% of 400 = 400
                                                50% of 400 = 200   --> 400+400+200=1,000


5) Combining Percents


A herd of 100 caribou was moved to a new location. The population increased by 10% the 1st year, then increased by 20% the next year.

Find the population of the second year:

10÷100= 0.10 -------> 1st Year ------> 0.10x100= 10 (increase)        100+10= 110
                                     2nd year -------> 0.20x110= 22 (increase)        110=22= 132
         

You can't use 30%, because you'll end up with a different wrong number.