Fraction Frenzy: Adding Fractions with Unlike Denominators

Mathematics Grades 7th Grade 7:23 Video
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Lesson Description

Master the art of adding fractions with different denominators! Learn how to find common denominators and combine fractions like a pro.

Video Resource

Adding fractions with unlike denominators

Khan Academy

Duration: 7:23
Watch on YouTube

Key Concepts

  • Fractions
  • Denominators
  • Numerators
  • Equivalent Fractions
  • Least Common Multiple (LCM)
  • Adding Fractions

Learning Objectives

  • Students will be able to identify the numerator and denominator of a fraction.
  • Students will be able to find the least common multiple (LCM) of two or more numbers.
  • Students will be able to create equivalent fractions with a common denominator.
  • Students will be able to add fractions with unlike denominators.

Educator Instructions

  • Introduction (5 mins)
    Begin by reviewing what fractions are and the meaning of numerator and denominator. Ask students for examples of fractions they encounter in everyday life (e.g., sharing a pizza, measuring ingredients). Briefly discuss why adding fractions with the same denominator is straightforward.
  • Video Presentation (10 mins)
    Play the Khan Academy video: 'Adding fractions with unlike denominators'. Instruct students to pay attention to how the video explains finding a common denominator and creating equivalent fractions.
  • Guided Practice (15 mins)
    Work through example problems on the board. Start with simpler examples and gradually increase the complexity. Emphasize the steps: 1) Find the LCM of the denominators. 2) Create equivalent fractions with the LCM as the new denominator. 3) Add the numerators. 4) Simplify the resulting fraction if possible.
  • Independent Practice (15 mins)
    Provide students with a worksheet containing a variety of fraction addition problems with unlike denominators. Circulate the room to provide assistance and answer questions. Encourage students to work together and help each other, but ensure each student completes their own work.
  • Review and Wrap-up (5 mins)
    Review the key steps for adding fractions with unlike denominators. Answer any remaining questions. Preview the next lesson, which might involve subtracting fractions with unlike denominators or adding more than two fractions.

Interactive Exercises

  • Fraction Match
    Create cards with fractions and their equivalent forms. Students match the equivalent fractions to reinforce the concept of creating equivalent fractions before adding.
  • Online Fraction Addition Practice
    Use an online tool (e.g., Khan Academy exercises, IXL) to provide students with immediate feedback on their fraction addition skills. This provides opportunities for repeated practice and error correction.

Discussion Questions

  • Why do we need a common denominator to add fractions?
  • What are some strategies for finding the least common multiple (LCM)?
  • How do you create an equivalent fraction?

Skills Developed

  • Problem-solving
  • Critical thinking
  • Fraction manipulation
  • LCM Calculation
  • Attention to Detail

Multiple Choice Questions

Question 1:

What is the first step when adding fractions with unlike denominators?

Correct Answer: Find a common denominator.

Question 2:

What is a common denominator?

Correct Answer: A number that is a multiple of all the denominators in a set of fractions.

Question 3:

What is the least common multiple (LCM) of 4 and 6?

Correct Answer: 12

Question 4:

What fraction is equivalent to 1/2 with a denominator of 6?

Correct Answer: 3/6

Question 5:

What is 1/3 + 1/3?

Correct Answer: 2/3

Question 6:

What is 1/4 + 2/8?

Correct Answer: 1/2

Question 7:

What should you do after adding the numerators in fractions with a common denominator?

Correct Answer: Simplify the fraction, if possible.

Question 8:

Which of the following is NOT an equivalent fraction of 2/4?

Correct Answer: 5/8

Question 9:

To find the LCM, you need to find the _____ multiple that the denominators share.

Correct Answer: Smallest

Question 10:

What is 2/5 + 1/10?

Correct Answer: 5/10

Fill in the Blank Questions

Question 1:

The top number in a fraction is called the ______.

Correct Answer: numerator

Question 2:

The bottom number in a fraction is called the ______.

Correct Answer: denominator

Question 3:

A ______ is a number that is a multiple of two or more numbers.

Correct Answer: common multiple

Question 4:

Fractions that have the same value are called ______ fractions.

Correct Answer: equivalent

Question 5:

Before adding fractions with unlike denominators, you need to find a ______ ______.

Correct Answer: common denominator

Question 6:

The smallest common multiple of two numbers is called the ______.

Correct Answer: least common multiple

Question 7:

After adding fractions, you should always ______ your answer if possible.

Correct Answer: simplify

Question 8:

To create an equivalent fraction, you multiply both the numerator and the denominator by the same ______.

Correct Answer: number

Question 9:

If two fractions have the same denominator, you can add them by adding their ________.

Correct Answer: numerators

Question 10:

The least common multiple of 3 and 5 is ______.

Correct Answer: 15

Educational Standards

7.N.1:[Standard] Read, write, represent, and compare rational numbers, expressed as integers, fractions, and decimals. Explain and apply the concept of absolute value. 7.N.1.2:[Objective] Recognize and generate equivalent representations of rational numbers, including equivalent fractions. 7.N.2.5:[Objective] Model and solve problems using rational numbers involving addition, subtraction, multiplication, division, and positive integer exponents. 7.A.4.1:[Objective] Use properties of operations (associative, commutative, and distributive) to generate equivalent numerical and algebraic expressions containing rational numbers, grouping symbols and whole number exponents.

Teaching Materials

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