NC.2.MD.8 OA.1 NBT.6

Joel’s Trip to the Store

Domain

Measurement and Data

Operations and Algebraic Thinking Number and Operations in Base Ten

Cluster

Work with time and money.

Represent and solve problems involving addition & subtraction.

Use place value understanding and properties of operations to add and subtract.

Standard(s)

NC.2.MD.8 Solve word problems involving:

• Quarters, dimes, nickels, and pennies within 99¢, using ¢ symbols appropriately.
• Whole dollar amounts, using the $ symbol appropriately.

NC.2.OA.1 Represent and solve addition and subtraction word problems, within 100, with unknowns in all positions, by using representations and equations with a symbol for the unknown number to represent the problem, when solving:

• Two-Step problems involving single digits: o Add to/Take From- Result Unknown

NC.1.NBT.6 Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90, explaining the reasoning, using:

• Concrete models and drawings
• Number lines
• Strategies based on place value
• Properties of operations
• The relationship between addition and subtraction

Materials

SF, pencil

Task

Provide the materials to the student. Read the problem to the student: Joel went to the store and bought three items. He bought a pencil for a dime, an eraser for 38¢, and a pencil sharpener for a quarter. How much money did Joel spend at the store? Explain your reasoning with numbers and

words.

Continuum of Understanding

Not Yet Proficient

• Provide instruction on making sense of the situation as a missing addend problem
• Provide conceptual instruction on making sense of the situation as an add to result unknown problem
• Provide instruction on place value when adding and subtracting with regrouping
• Provide instruction on identifying dimes and quarters and relating their value to pennies (1st grade NC.1.MD.5)

1. Solves the problem correctly
2. Clearly explains their thinking

Strategy(ies) Used:

1. Counting All
2. Counting On
3. Makes Tens
4. Basic Facts
5. Creates easier or known sums
6. Doubles
7. Doubles +/- 1, 2
8. Other: Knows value of:
9. Dime
10. Quarter

Progressing

• Incorrectly identifies the value of a quarter and/or dime.
• Incorrectly solves the problem.
• Relies on counting as primary strategy for solving problem.
• Explanation is lacking in detail or non-existent.

Meets Expectation

• Correctly solves the problem: 73¢
• Successfully uses strategies such as making tens, creates easier or known sums, and basic facts.

• Explanation is clear and indicates understanding of the value of the coins and illustrates strategies used to solve the problem.
• Equation includes a symbol for the unknown number
• Explanation is clear and uses numbers, pictures, or words to show their thinking.

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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.