 Author:
 DAWNE COKER
 Subject:
 Mathematics
 Material Type:
 Activity/Lab, Assessment, Formative Assessment
 Level:
 Lower Primary
 Tags:
 License:
 Creative Commons Attribution
 Language:
 English
 Media Formats:
 Downloadable docs
Education Standards
Gree Apples
How Many Quarters
Jacueline's Missing Number
T4T Solving Unknown Addend Problems
Overview
This resource is from Tools4NCTeachers.
This file contains a set of 4 tasks (including scoring rubric and student recording sheet). The tasks may be used for instruction or assessment. Each focuses on solving a problem with an unknown addend.
Remix this resource to include student work samples or addtional tasks.
Here is a sample task from this resource. Click each attachment to access all fullyformatted tasks, rubrics, and materials.
NC.1.OA.4 Bob’s Missing Number  
Domain  Operations and Algebraic Thinking 
Clusters  Understand and apply the properties of operations. Add and subtract within 20. 
Standards  NC.1.OA.4 Solve an unknownaddend problem, within 20, by using addition strategies and/or changing it to a subtraction problem. NC.1.OA.6 Add and subtract, within 20, using strategies such as:

Materials  SF, pencil 
Task  Read the problem aloud to the student. Bob is trying to find the missing number in the following equation: 6 + ? = 13. How would you help Bob find the missing number? Show your work using pictures, numbers, or words. Be sure you tell what number is needed to complete the equation. 
Continuum of Understanding  
Not Yet Proficient  Response includes 01 of the descriptors in “Meets Expectations”  Strategies Used:

Progressing  Response includes 2 of the descriptors in “Meets Expectations”
 
Meets Expectations  Response includes all the descriptors in “Meets Expectations”

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. 
Bob is trying to find the missing number in the following equation: 6 + ? = 13. How would you help Bob find the missing number?
Show your work using pictures, numbers, or words. Be sure you tell what number is needed to complete the equation.

Scoring Examples
This student received “Not Yet Proficient” because the student did not create a model or an equation to correctly represent the problem. The student created two models in which the known numbers were added together to get a total of 19 and then incorrectly inserted the 19 into the equation 6 + 19 = 13. This student could benefit from using concrete representations to help understand the meaning of the equal sign as well as strategies for solving a problem with a missing addend.
This student received “Progressing” because the student could solve the problem correctly using addition, but did not clearly explain the addition strategy. There were 8 hops on the number line instead of 7 and the 13 was circled in the equation, which indicates a possible confusion about the unknown. This student could benefit from additional opportunities to use and explain the number line strategy. This might sound like, “I started at 6 and counted up 7 more until I got to 13.”
These students received “Meets Expectations” because they could correctly solve and clearly explain the thinking done to solve the problem. Their strategies included using known facts and making a ten to solve.