Adding and Subtracting Fractions

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Adding and Subtracting Fractions

• Adding and Subtracting Fractions

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Objectives

• Students will be able to find the least common
  denominator in order to add and subtract
  fractions with different denominators.
• Students will be able to find the least common
  multiple in order to get the least common
  denominator.

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Warm-up

• How can we add
• 1/3 1/2 ?

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How to add 1/31/5 ?

• Step 1 List prime factor of 3 and 5
• 3 5

5
1
1
3
Least Common Denominator
X
X

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How to add 1/31/5 ?

• Step 2 multiply the numerator and denominator by
  the same factor to make equivalent fractions.

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How to add 1/61/12 ?

• Step 1 List prime factor of 3 and 5
• 6 12

1
2
2
1
3
3
2
Least Common Denominator
12
X
X
X

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How to add 1/61/12 ?

• Step 2 multiply the numerator and denominator by
  the same factor to make equivalent fractions.

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Group Practice

• GO!

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How to add 5/8-3/6?

• Step 1 List prime factor of 6 and 12
• 8 6

Least Common Denominator

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How to add 5/8 - 3/6

• Step 2 multiply the numerator and denominator by
  the same factor to make equivalent fractions.

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Individual practice
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More exercise

• Review
• Find the LCM
• Video Clip to review LCD
• Adding Fractions
• Subtracting Fractions

• On-line Practice
• Practice (LCM)
• Practice (LCD)
• Adding Fractions
• Subtracting Fractions