Multiplying Fractions

Multiplying Fractions

Unit 2

Poll

Do the denominators have to be the same when you are multiplying fractions?

• YES

• NO

NO!!!

• When you are MULTIPLYING/DIVIDING fractions, you DO NOT have to have the same denominators!!!!!!

• Ex:

   $\frac{1}{3}\times\frac{2}{5}=\frac{2}{15}$ 

Here is how you will multiply fractions.............

•  $\frac{4\Longrightarrow}{5\Longrightarrow}x\ \frac{1}{3}=\frac{4}{15}$  

•  $4\times1=4\ ,\ \ 5\times3=15$  

LET'S PRACTICE!

•  $\frac{1}{2}\times\frac{3}{4}$  

•  $\frac{5}{6}\times\frac{1}{2}$  

•  $\frac{7}{8}\times\frac{3}{5}$  

•  $\frac{2}{3}\times\frac{1}{7}$  

WHEN DIVIDING FRACTIONS YOU HAVE TO USE KCF!

• K- EEP

• C-HANGE

• F-LIP

KCF METHOD

•  $\frac{3}{2\ }\div\frac{1}{9}$  

• KEEP  $\frac{3}{2}$  

• CHANGE  $\div$  TO  $\times$  

• FLIP  $\frac{1}{9}$  TO  $\frac{9}{1}$  

• REWRITE  $\frac{3}{2}\times\frac{9}{1}=\ \frac{27}{2}$  

Multiple Choice

DIVIDE....

 $\frac{3}{2}\div\frac{1}{9}$  

•  $\frac{3}{6}$  

•  $\frac{27}{2}$  

•  $\frac{3}{18}$  

LET'S TRY KCF METHOD!

•  $\frac{3}{5}\div\frac{1}{2}$  

•  $\frac{1}{5}\div\frac{1}{3}$  

•  $\frac{2}{7}\div\frac{2}{5}$  

•  $\frac{4}{5}\div\frac{1}{3}$  

•  $\frac{4}{5}\div\frac{2}{3}$  

YOU DO!!!!!!!!!

Multiple Choice

 $\frac{3}{7}\times\frac{3}{4}$  

•  $\frac{12}{21}$  

•  $\frac{9}{28}$  

•  $\frac{21}{12}$  

Open Ended

 $\frac{1}{8}\times\frac{3}{7}$  

TRY THESE!

•  $\frac{3}{5}\times\frac{1}{8}$  

•  $\frac{3}{5}\div\frac{1}{8}$  

•  $\frac{1}{9}\div\frac{6}{8}$  

•  $\frac{6}{10}\times\frac{1}{3}$  

•  $\frac{5}{9}\times\frac{1}{8}$  

Poll

How do you feel about multiplying fractions?

• Great

• Okay

• I need more practice