Learn on PengiIllustrative Mathematics, Grade 6Unit 4 Dividing Fractions

Lesson 2: Meanings of Fraction Division

In this Grade 6 Illustrative Mathematics lesson from Unit 4: Dividing Fractions, students explore the two core meanings of fraction division — "how many groups?" and "how many in each group?" — and learn to distinguish between them using diagrams and equations. Students connect fraction division to related multiplication equations, building conceptual understanding before applying procedures.

Section 1

Two Meanings of Division: Quotative and Partitive

Property

Division word problems can be categorized into two types based on the unknown information:

  1. Group Size Unknown (Partitive Division): The total is divided into a known number of groups. The goal is to find the size of each group.
Total÷Number of Groups=? (Group Size)Total \div Number\ of\ Groups = ?\ (Group\ Size)
  1. Number of Groups Unknown (Quotative Division): The total is divided by a known group size. The goal is to find the number of groups.
Total÷Group Size=? (Number of Groups)Total \div Group\ Size = ?\ (Number\ of\ Groups)

Section 2

Modeling Quotative Division: Finding the Number of Groups

Property

To find an unknown number of groups, you can model division by starting with the total amount (dividend) and creating groups of a known size (divisor). The number of groups you make is the answer (quotient). This can be represented as:

Total÷SizeperGroup=NumberofGroupsTotal \div Size\:per\:Group = Number\:of\:Groups

Examples

Section 3

Modeling Quotative Division: Whole Number ÷ Unit Fraction

Property

Dividing a whole number, aa, by a unit fraction, 1b\frac{1}{b}, is a way of asking: "How many groups of size 1b\frac{1}{b} are in aa?"
This can be modeled visually to find the total number of fractional parts.

Examples

Section 4

Modeling Partitive Division: Finding the Group Size

Property

To find the amount for a single share in an equal sharing situation (Partitive Division), divide the total amount by the number of shares. The result can be expressed as a fraction or a mixed number.

Size of one share=Total amountNumber of shares\text{Size of one share} = \frac{\text{Total amount}}{\text{Number of shares}}

Examples

  • To model 3÷43 \div 4, draw a tape diagram representing the whole number 3, and divide it into 4 equal parts. The value of one part is 34\frac{3}{4}.
  • To model 5÷25 \div 2, draw 5 tape diagrams, each representing 1 whole. To share them into 2 equal groups, each group receives 2 whole tapes and 12\frac{1}{2} of the last tape, showing that 5÷2=2125 \div 2 = 2\frac{1}{2}.

Book overview

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Unit 4 Dividing Fractions

  1. Lesson 1

    Lesson 1: Making Sense of Division

  2. Lesson 2Current

    Lesson 2: Meanings of Fraction Division

  3. Lesson 3

    Lesson 3: Algorithm for Fraction Division

  4. Lesson 4

    Lesson 4: Fractions in Lengths, Areas, and Volumes

Lesson overview

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Section 1

Two Meanings of Division: Quotative and Partitive

Property

Division word problems can be categorized into two types based on the unknown information:

  1. Group Size Unknown (Partitive Division): The total is divided into a known number of groups. The goal is to find the size of each group.
Total÷Number of Groups=? (Group Size)Total \div Number\ of\ Groups = ?\ (Group\ Size)
  1. Number of Groups Unknown (Quotative Division): The total is divided by a known group size. The goal is to find the number of groups.
Total÷Group Size=? (Number of Groups)Total \div Group\ Size = ?\ (Number\ of\ Groups)

Section 2

Modeling Quotative Division: Finding the Number of Groups

Property

To find an unknown number of groups, you can model division by starting with the total amount (dividend) and creating groups of a known size (divisor). The number of groups you make is the answer (quotient). This can be represented as:

Total÷SizeperGroup=NumberofGroupsTotal \div Size\:per\:Group = Number\:of\:Groups

Examples

Section 3

Modeling Quotative Division: Whole Number ÷ Unit Fraction

Property

Dividing a whole number, aa, by a unit fraction, 1b\frac{1}{b}, is a way of asking: "How many groups of size 1b\frac{1}{b} are in aa?"
This can be modeled visually to find the total number of fractional parts.

Examples

Section 4

Modeling Partitive Division: Finding the Group Size

Property

To find the amount for a single share in an equal sharing situation (Partitive Division), divide the total amount by the number of shares. The result can be expressed as a fraction or a mixed number.

Size of one share=Total amountNumber of shares\text{Size of one share} = \frac{\text{Total amount}}{\text{Number of shares}}

Examples

  • To model 3÷43 \div 4, draw a tape diagram representing the whole number 3, and divide it into 4 equal parts. The value of one part is 34\frac{3}{4}.
  • To model 5÷25 \div 2, draw 5 tape diagrams, each representing 1 whole. To share them into 2 equal groups, each group receives 2 whole tapes and 12\frac{1}{2} of the last tape, showing that 5÷2=2125 \div 2 = 2\frac{1}{2}.

Book overview

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

Continue this chapter

Unit 4 Dividing Fractions

  1. Lesson 1

    Lesson 1: Making Sense of Division

  2. Lesson 2Current

    Lesson 2: Meanings of Fraction Division

  3. Lesson 3

    Lesson 3: Algorithm for Fraction Division

  4. Lesson 4

    Lesson 4: Fractions in Lengths, Areas, and Volumes