Percentages in everyday life

Percents.  Means “per 100”.  Percents can be written as fractions by placing the number over 100 and simplifying.

 

Percents.   Percents can be written as decimals (1) moving the 
decimal point 2 places to the left, and (2) deleting the percent sign.

 

Percent formula








Example: 4% of 50 is____ 






or      50 x 4% = 50 X 0.04 = 2

Example:         10% of X is 15,   find X

X*10%=15
 
X=15/10% = 15/0.10=150
Percent of change
 

 

 


Percentage change between two numbers A & B can be calculated
 as:
(B-A)/A * 100

For example, if a game price increases in value from $10 to $12 
the percentage increase is: 

(12-10)/10 * 100 = 2/10 *100 = 0.2*100 = 20 percent 

Alternatively, if a game price decreases in value from $10 to $9 the
percentage decrease is: 

(10-9)/10 * 100 = 0.1*100 = 10 percent


Convert Fractions, Decimals, Percents

                                                                                 Move the decimal point twice to the right
Move the decimal point twice to the left, 
delete the percent sign
Write down the decimal divided by 1
Multiply its numerator and denominator
by the same  number (10, 100, 1000, ..)
Simplify if necessary
 
 
 



To convert a decimal to a percent, multiply the decimal by 100, 
                                  then add on the % symbol.