A Piece of Yarn
3.NF.2 and 3.NF.3 Task 2

Domain

Number and Operations – Fractions

Cluster

Develop understanding of fractions as numbers.

Standard(s)

3.NF.2 Understand a fraction as a number on the number line; represent fractions on a number line diagram.
3.NF.3 Explain equivalence of fractions in special cases, and compare fractions by reasoning about their size.

Materials

Student activity sheet, paper, pencils, white boards and dryerase markers (optional)

Task

Part 1: Suni was using the following yard stick to measure pieces of yarn for her art project. This ruler shows how much yarn she cuts for each color. What fraction of a unit does she need of each color?
Part 2: If the unit was divided into fourths, which colors of string could be measured in fourths? How many fourths is each of those colors? Explain your answer using pictures or words.
Part 3: Are any of the colors equal to ½ of the unit? Write a sentence explaining your reasoning.

Rubric

Level I
 
Level II

Level III

Limited Performance
 
Not Yet Proficient

Proficient in Performance

Accurately solves Part 1: Blue: 1/8, Green: 4/8, Red 6/8.

Accurately solves Part 2: Green and Red can be measured in fourths. Green: 2/4. Red: 3/4.

Accurately solves Part 3: Green.

Writes clear and appropriate explanations.

*Level IV would be to include other equivalent fractions.
Standards for Mathematical Practice

1. Makes sense and perseveres in solving problems.

2. Reasons abstractly and quantitatively.

3. Constructs viable arguments and critiques the reasoning of others.

4. Models with mathematics.

5. Uses appropriate tools strategically.

6. Attends to precision.

7. Looks for and makes use of structure.

8. Looks for and expresses regularity in repeated reasoning.

A Piece of Yarn
Suni was using the following yard stick to measure pieces of yarn for her art project. This ruler shows how much yarn she cuts for each color.
What fraction of a unit does she need of each color?
If the unit was divided into fourths, which colors of string could be measured in fourths?
How many fourths is each of those colors? Explain your answer using pictures or words.
Are any of the colors equal to ½ of the unit? Write a sentence explaining your reasoning.
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