Adding and subtracting Fractions with Uncommon Denominator

Adding and subtracting Fractions with Uncommon Denominator

I can use equivalent fractions to find a common denominator and add or subtract fractions and mixed numbers.

First Find common Denominators!

You can multiply the two denominators

Or you can find a common multiple of both denominators.

Remember what ever you do to the denominator, you must also do to the numerator.

Multiple Select

Which of these could be a common denominator for $\frac{3}{8}$   and  $\frac{1}{4}$  ?

• 8

• 12

• 20

• 24

• 32

Guided Practice

• Step 1- Rewrite the equation, change the mixed number to an improper Fraction.

• Step 2 Find a common Denominator.

• step 3 WRite Equivalent fractions.

Fill in the Blanks

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Remember

• Multiply the Numerator and Denominator by the same number.

• Add the Numerators only. The Denominators stay the same.

Open Ended

What must you do before adding or subtracting unlike fractions?

Open Ended

How can you find a common denominator for two unlike fractions?

Multiple Choice

 $\frac{3}{8\ }\ +\frac{3}{4}\ =$  Write your answer in simplest form. 

•  $\frac{9}{16}$  

•  $1\ \frac{1}{8}$  

•  $\frac{6}{8}$  

•  $\frac{6}{12}$  

Multiple Choice

 $2\ \frac{1}{3\ }\ -\ 1\ \frac{1}{2}\ =\ Write\ your\ answer\ in\ simplest\ form.\$  

•  $\frac{5}{6}$  

•  $\frac{4}{6}$  

•  $\frac{4}{1}$  

•  $1\ \frac{5}{6}$  

Multiple Choice

 $2\ \frac{1}{2}\ +1\ \frac{3}{4}$  Write your answer in simplest Form. 

•  $3\ \frac{5}{4}$  

•  $3\ \frac{4}{6}$  

•  $3\ \frac{4}{4}$  

•  $4\ \frac{1}{4}$  

Multiple Choice

 $3\ -2\ \frac{1}{5}=\ Write\ your\ answer\ in\ simplest\ form.$  

•  $1\ \frac{1}{5}$  

•  $2\ \frac{4}{5}$  

•  $\frac{4}{5}$  

•  $5\ \frac{1}{5}$