Fractions, Decimals and Percents

Fractions, Decimals and Percents

Changing a fraction to a decimal

• Divide the numerator (top) by the denominator (bottom)

• The top number goes inside!!!

• Example - Change to a decimal

   $\frac{3}{5}$  is   $3\div5$  

Change a Decimal to a Percent

• Multiply it by 100 (which is moving the decimal to the right 2 places)

• Example Change 0.75 to a percent -
  
  

   $0.75\times100=75\%$  
  

• Example - Change 2.46 to a percent    -  $2.46\times100=246\%$ 

Change a Percent to a Decimal

• Divide your percent by 100. ( Move the decimal point 2 places to the left)

• Example

   $80\%\div100=0.8$  

• Example  $245\%\div100=2.45$  

Changing a decimal to a fraction

• Write your fraction as you read it! Your denominator is the last decimal place.

• Example - 0.3 is read "Zero and 3 tenths" , the fraction is

   $\frac{3}{10}$  

• Example 1.25 is read " one and 25 hundredths", the fraction is   $1\frac{25}{100}=1\ \frac{1}{4}$  

Percent to Fraction

• Percent is a ratio "per 100"

• Put your percent in a fraction with a denominator of 100 and then simplify.

• Example  $30\%=\frac{30}{100}=\frac{3}{10}$   

  
  

• Example  $120\%\ =\ \frac{120}{100}=1\ \frac{1}{5}$  

Fraction to Percent

• Change the fraction to a decimal and then to a percent

•  $\frac{3}{5}=0.6=60\%$  

•  $1\ \frac{1}{5}=1.2=120\%$