Learn on PengiPengi Math (Grade 5)Chapter 6: Multiplying and Dividing Fractions

Lesson 5: Multiplying Mixed Numbers

In this Grade 5 Pengi Math lesson from Chapter 6, students learn how to multiply mixed numbers by first converting them to improper fractions and applying fraction multiplication strategies. Area models are used to connect the process to the distributive property, reinforcing conceptual understanding. Students also practice interpreting their results in real-world contexts to build meaningful number sense.

Section 1

Convert Mixed Numbers to Improper Fractions

Property

To convert a mixed number AbcA\frac{b}{c} to an improper fraction, use the formula:

Abc=(A×c)+bcA\frac{b}{c} = \frac{(A \times c) + b}{c}

Examples

  • 213=(2×3)+13=732\frac{1}{3} = \frac{(2 \times 3) + 1}{3} = \frac{7}{3}
  • 534=(5×4)+34=2345\frac{3}{4} = \frac{(5 \times 4) + 3}{4} = \frac{23}{4}

Explanation

A mixed number consists of a whole number and a fraction. To convert it to an improper fraction, first multiply the whole number part by the fraction''s denominator. Next, add the numerator to this product to get the new numerator. The denominator of the improper fraction remains the same as the original fraction''s denominator.

Section 2

Multiply Mixed Numbers Using Improper Fractions

Property

To multiply mixed numbers, follow these steps:

  1. Convert: Change each mixed number into an improper fraction using the formula abc=(a×c)+bca\frac{b}{c} = \frac{(a \times c) + b}{c}.
  2. Multiply: Multiply the numerators, and multiply the denominators.
  3. Simplify: Simplify the resulting fraction and convert it back to a mixed number if needed.

Examples

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Chapter 6: Multiplying and Dividing Fractions

  1. Lesson 1

    Lesson 1: Fractions as Division

  2. Lesson 2

    Lesson 2: Multiplying a Fraction by a Whole Number

  3. Lesson 3

    Lesson 3: Multiplying Fractions Using Area Models

  4. Lesson 4

    Lesson 4: The Standard Algorithm for Fraction Multiplication

  5. Lesson 5Current

    Lesson 5: Multiplying Mixed Numbers

  6. Lesson 6

    Lesson 6: Division of Unit Fractions by Whole Numbers

  7. Lesson 7

    Lesson 7: Division of Whole Numbers by Unit Fractions

  8. Lesson 8

    Lesson 8: Solving Fraction Word Problems with Multiplication and Division

Lesson overview

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Section 1

Convert Mixed Numbers to Improper Fractions

Property

To convert a mixed number AbcA\frac{b}{c} to an improper fraction, use the formula:

Abc=(A×c)+bcA\frac{b}{c} = \frac{(A \times c) + b}{c}

Examples

  • 213=(2×3)+13=732\frac{1}{3} = \frac{(2 \times 3) + 1}{3} = \frac{7}{3}
  • 534=(5×4)+34=2345\frac{3}{4} = \frac{(5 \times 4) + 3}{4} = \frac{23}{4}

Explanation

A mixed number consists of a whole number and a fraction. To convert it to an improper fraction, first multiply the whole number part by the fraction''s denominator. Next, add the numerator to this product to get the new numerator. The denominator of the improper fraction remains the same as the original fraction''s denominator.

Section 2

Multiply Mixed Numbers Using Improper Fractions

Property

To multiply mixed numbers, follow these steps:

  1. Convert: Change each mixed number into an improper fraction using the formula abc=(a×c)+bca\frac{b}{c} = \frac{(a \times c) + b}{c}.
  2. Multiply: Multiply the numerators, and multiply the denominators.
  3. Simplify: Simplify the resulting fraction and convert it back to a mixed number if needed.

Examples

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 6: Multiplying and Dividing Fractions

  1. Lesson 1

    Lesson 1: Fractions as Division

  2. Lesson 2

    Lesson 2: Multiplying a Fraction by a Whole Number

  3. Lesson 3

    Lesson 3: Multiplying Fractions Using Area Models

  4. Lesson 4

    Lesson 4: The Standard Algorithm for Fraction Multiplication

  5. Lesson 5Current

    Lesson 5: Multiplying Mixed Numbers

  6. Lesson 6

    Lesson 6: Division of Unit Fractions by Whole Numbers

  7. Lesson 7

    Lesson 7: Division of Whole Numbers by Unit Fractions

  8. Lesson 8

    Lesson 8: Solving Fraction Word Problems with Multiplication and Division