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  $$\frac{3}{8}$$  ?

• 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 Blank

What are your new Numerators?

,

Fill in the Blank

What is your answer?

Use your numerators from the previous question.

Fill in the Blank

13/ 6 = 2 __/6

Remember

• Multiply the Numerator and Denominator by the same number.

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

Fill in the Blank

To find an equivalent fraction, multiply the numerator and the denominator by the ________ number.

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.\$$  

• $$\frac{5}{6}$$  

• $$\frac{4}{6}$$  

• $$\frac{4}{1}$$  

• $$1\ \frac{5}{6}$$