Addition of Fractions
10 min
Narrative
The purpose of this Warm-up is to activate what students know about the use of number lines to represent fractional values, preparing them to use number lines to reason about addition of fractions in a later activity. While students may notice and wonder many things about the diagram, be sure to highlight the meaning of each interval and where the numbers 1 and 2 are located on the number line.
Launch
- Groups of 2
- Display the number-line diagram.
- “What do you notice? What do you wonder?”
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Share and record responses.
Student Task
What do you notice? What do you wonder?
Sample Response
Students may notice:
- There are 5 tick marks from 0 to 35.
- Each space between tick marks represents 31.
- There are no other numbers on the line.
- There are 5 groups of 31.
Students may wonder:
- Why is 35 labeled?
- Why aren’t the other tick marks labeled?
- Where is 1 on the number line? Why isn’t 1 shown?
Activity Synthesis (Teacher Notes)
- “What does the space between any two tick marks represent?” (A third.) “How do you know?” (If five spaces represent 5 thirds and the spaces are the same size, then each space is 1 third.)
- “Where is 1 on the number line?” (The third tick mark from 0.) “Where is 2?” (The sixth tick mark from 0, or 1 tick mark to the right of 35.)
- “Today we’ll use number lines to help us reason about sums of fractions.”
Standards
Building Toward
- 4.NF.3.b·Decompose a fraction into a sum of fractions with the same denominator in more than one way, recording each decomposition by an equation. Justify decompositions, e.g., by using a visual fraction model.
- 4.NF.B.3.b·Decompose a fraction into a sum of fractions with the same denominator in more than one way, recording each decomposition by an equation. Justify decompositions, e.g., by using a visual fraction model. <span>Examples: <span class="math">\(\frac38 = \frac18 + \frac18 + \frac18\)</span>; <span class="math">\(\frac38 = \frac18 + \frac28\)</span>; <span class="math">\(2 \frac18 = 1 + 1 + \frac18 = \frac88 + \frac88 + \frac18.\)</span></span>
20 min
15 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Addition of Fractions
10 min
Narrative
The purpose of this Warm-up is to activate what students know about the use of number lines to represent fractional values, preparing them to use number lines to reason about addition of fractions in a later activity. While students may notice and wonder many things about the diagram, be sure to highlight the meaning of each interval and where the numbers 1 and 2 are located on the number line.
Launch
- Groups of 2
- Display the number-line diagram.
- “What do you notice? What do you wonder?”
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Share and record responses.
Student Task
What do you notice? What do you wonder?
Sample Response
Students may notice:
- There are 5 tick marks from 0 to 35.
- Each space between tick marks represents 31.
- There are no other numbers on the line.
- There are 5 groups of 31.
Students may wonder:
- Why is 35 labeled?
- Why aren’t the other tick marks labeled?
- Where is 1 on the number line? Why isn’t 1 shown?
Activity Synthesis (Teacher Notes)
- “What does the space between any two tick marks represent?” (A third.) “How do you know?” (If five spaces represent 5 thirds and the spaces are the same size, then each space is 1 third.)
- “Where is 1 on the number line?” (The third tick mark from 0.) “Where is 2?” (The sixth tick mark from 0, or 1 tick mark to the right of 35.)
- “Today we’ll use number lines to help us reason about sums of fractions.”
Standards
Building Toward
- 4.NF.3.b·Decompose a fraction into a sum of fractions with the same denominator in more than one way, recording each decomposition by an equation. Justify decompositions, e.g., by using a visual fraction model.
- 4.NF.B.3.b·Decompose a fraction into a sum of fractions with the same denominator in more than one way, recording each decomposition by an equation. Justify decompositions, e.g., by using a visual fraction model. <span>Examples: <span class="math">\(\frac38 = \frac18 + \frac18 + \frac18\)</span>; <span class="math">\(\frac38 = \frac18 + \frac28\)</span>; <span class="math">\(2 \frac18 = 1 + 1 + \frac18 = \frac88 + \frac88 + \frac18.\)</span></span>