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.\$$  

• $$\frac{5}{6}$$  

• $$\frac{4}{6}$$  

• $$\frac{4}{1}$$  

• $$1\ \frac{5}{6}$$