Adding and subtracting fractions with unlike denominators

Adding and Subtracting fractions with UNLIKE denominators

Do you have a common denominator?

Are the denominators the same?

If you answered No........

• Find the Least Common Denominator (LCD)

• Then ADD or Subtract the numerators

Poll

Can we add or subtract fractions with UNLIKE Denominators?

• Yes

• No

• I'm unsure

Poll

Can we add 

 $\frac{2}{3}+\frac{3}{12}$  

• Yes 

• No

Multiple Choice

Find the Least Common Denominator(LCD) for

 $\frac{2}{3}+\frac{3}{12}$  

• 24

• 12

• 36

Multiple Choice

 $\frac{1}{4}+\frac{2}{3}=$  

•  $\frac{3}{12}$  

•  $\frac{3}{4}$  

•  $\frac{11}{12}$  

•  $\frac{3}{7}$  

Multiple Choice

What is the LCM of 2, 4, 6?

• 6

• 12

• 4

• 2

Multiple Choice

Use a number tree to find the prime factorization of 34

• 2x2x2x4
• 2x2x2x2x2
• 4x4x2
• 2x2x2x2x1

Multiple Choice

Choose the correct list of the first five multiples of 10.

• 1, 10, 20, 30, 40
• 10, 20, 30, 40, 50
• 5, 10, 15, 20, 25
• 10, 30, 40, 50, 60

Multiple Choice

I ate 1/3 of a pizza. Cody ate 1/2 of the same pizza. How much did we eat of the pizza?

• 5/6

• 1 whole

• 2/6

• 9/12

Multiple Choice

• 6/9

• 10/9

• 2/3

• 1 1/9

Multiple Choice

Is this a correct answer?

• Yes, the student correctly added.

• No, you cannot add unlike denominators

• No, 5 + 7 is not 12

• No, 2 + 3 is not 5

Multiple Choice

What fraction of the rectangle is blue?

• 1/6

• 1/3

• 6/2

• 2/3

Multiple Choice

 $\frac{3}{5}-\frac{2}{6}$  

• 0

•  $\frac{1}{3}$  

•  $\frac{1}{30}$  

•  $\frac{4}{15}$  

Multiple Choice

Estimate: $\frac{2}{3}-\frac{1}{9}$  

•  $\frac{5}{9}$  

• 0

•  $\frac{1}{2}$  

•  $\frac{1}{6}$  

GREAT JOB!

DON'T WORRY WE HAVE MORE PRACTICE LATER!!!!!

Multiple Select

REMEMBER: YOU MUST HAVE A COMMON DENOMINATOR WHEN ADDING AND SUBTRACTING DENOMINATORS!!!

• FIND THE LEAST COMMON DENOMINATOR.

• ADD OR SUBTRACT THE NUMERATORS AS NORMAL.

• MAKE SURE THAT YOU SIMPLIFY YOUR ANSWERS.

NEXT WEEK WE WILL LOOK AT MULTIPLYING AND DIVIDING FRACTIONS

HINT: YOU DO NOT HAVE TO HAVE THE SAME DENOMINATORS WHEN YOU ARE MULTIPLYING AND DIVIDING FRACTIONS!!!!!!

Multiple Choice

Find the product:

• 9/24
• 9/28
• 6/32
• 1/28