Adding and Subtracting Fractions with Unlike Denominators

This video tutorial explains how to add and subtract fractions with unlike denominators. It covers finding a common denominator using the least common multiple (LCM), converting fractions to have the same denominator, and performing addition and subtraction. The tutorial includes examples and demonstrates how to simplify the resulting fractions.

Why is it necessary to have common denominators when adding or subtracting fractions?

• To make the denominators equal

• To ensure the fractions are comparable

• To simplify the fractions

• To make the numerators equal

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CCSS.4.NF.A.2

CCSS.4.NF.C.5

What is the first step in finding a common denominator for fractions?

• Adding the numerators

• Multiplying the fractions

• Subtracting the denominators

• Finding the least common multiple (LCM)

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CCSS.4.NF.A.2

How do you find the least common multiple (LCM) of two numbers?

• By dividing the larger number by the smaller number

• By subtracting the smaller number from the larger number

• By listing the multiples of each number until a common multiple is found

• By adding the two numbers

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CCSS.6.NS.B.4

What is the least common multiple (LCM) of 3 and 4?

• 6

• 8

• 16

• 12

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CCSS.4.OA.B.4

When converting fractions to have the same denominator, what must you do to the numerator?

• Multiply the numerator by the same factor used for the denominator

• Divide the numerator by the same factor used for the denominator

• Add the same number to the numerator

• Subtract the same number from the numerator

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CCSS.4.NF.A.1

What is the result of adding 3/4 and 1/3 after converting to a common denominator?

• 1 and 1/12

• 13/12

• 9/12

• 4/7

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CCSS.4.NF.A.2

How do you simplify the fraction 13/12?

• By adding 1 to the denominator

• By converting it to a mixed number

• By dividing both the numerator and the denominator by 2

• By subtracting 1 from the numerator

What is the least common multiple (LCM) of 2 and 3?

• 3

• 4

• 5

• 6

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CCSS.4.OA.B.4

What is the result of subtracting 1/2 from 2/3 after converting to a common denominator?

• 1/4

• 1/6

• 1/3

• 1/2

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CCSS.4.NF.A.2

What is the final simplified result of subtracting 1/3 from 3/4?

• 1/2

• 5/12

• 1/3

• 1/4

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CCSS.5.NF.A.2