Fractions

Fractions

Adding and Subtracting Fractions

1) Turn mixed numbers into improper fractions

2) Find the least common denominator

3) Change both fractions so they have a common denominator

4) Add or subtract the fractions

5) Change back into a mixed number if necessary

Adding Fractions - Example

•  $\frac{1}{2}+\frac{2}{3}$  
  

• Count by 2s and 3s - least common denominator is 6

•  $\frac{1\times3}{2\times3}+\frac{2\times2}{3\times2}$  

•  $\frac{3}{6}+\frac{4}{6}$  
  

•  $\frac{7}{6}$   

•  $1\ \frac{1}{6}$  

Multiple Choice

 $\frac{2}{3}+\frac{1}{4}$  

•  $\frac{3}{7}$  

•  $\frac{11}{12}$  

Multiple Choice

 $\frac{9}{10}-\frac{1}{5}$  

•  $\frac{7}{10}$  

•  $\frac{8}{5}$  

Multiplying Fractions

1) Change mixed numbers and whole numbers into improper fractions

2) Cross cancel and multiply across

OR

2) Multiply across and simplify

3) Change back into a mixed number if necessary

Multiplying Fractions - Example

•  $\frac{2}{3}\times\frac{9}{10}$  

•  $\frac{1}{1}\times\frac{3}{5}$  Cross Cancel

•  $\frac{3}{5}$  

Multiple Choice

 $\frac{1}{2}\times\frac{2}{3}$  

•  $\frac{1}{3}$  

•  $\frac{3}{4}$  

Multiple Choice

 $\frac{5}{6}\times\frac{1}{5}$  

•  $\frac{6}{25}$  

•  $\frac{1}{6}$  

Dividing Fractions

1) Change mixed numbers and whole numbers into improper fractions

2) Keep, change, flip

3) Cross cancel and multiply across

OR

3) Multiply across and simplify

4) Change back into a mixed number if necessary

Dividing Fractions - Example

•  $\frac{1}{2}\div\frac{3}{4}$  

•  $\frac{1}{2}\times\frac{4}{3}$  Keep, change , flip

•  $\frac{1}{1}\times\frac{2}{3}$  Cross cancel

•  $\frac{2}{3}$  

Multiple Choice

 $\frac{1}{2}\div\frac{2}{3}$  

•  $\frac{2}{6}$  

•  $\frac{3}{4}$  

Multiple Choice

 $\frac{4}{5}\div\frac{1}{5}$  

•  $\frac{4}{25}$  
  

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