General Information
Subject Area: Mathematics (B.E.S.T.)
Grade: 2
Strand: Algebraic Reasoning
Date Adopted or Revised: 08/20
Status: State Board Approved
Benchmark Instructional Guide
Connecting Benchmarks/Horizontal Alignment
Terms from the K-12 Glossary
- Associative Property of Addition
- Commutative Property of Addition
- Equation
- Expression
Vertical Alignment
Previous Benchmarks
Next Benchmarks
Purpose and Instructional Strategies
The purpose of this benchmark is to provide opportunities for students to solve various real-world situation types involving addition and subtraction. In grade 1, students solved real-world addition and subtraction problems within 20 (MTR.7.1).- Instruction includes experience with all situation types involving addition and subtraction.
- Mastery of all situation types, as shown in Appendix A, is expected at by the end of this grade level.
- Instruction leads students to focus on context and apply reasoning to determine the appropriate operation.
- Instruction includes the use of number lines, drawings, diagrams or models to represent problem context.
Common Misconceptions or Errors
- Students may have difficulty interpreting the quantities in the context of the problem or misidentifying the operation needed to solve the problem.
- Students may interpret a start or change unknown problem as a result unknown problem.
- Students may look for key words which can lead to the wrong operation and cause students to ignore context and reasoning.
Strategies to Support Tiered Instruction
- Teacher provides a graphic organizer to record information about the problem that focuses on the quantities in context and the operation(s) needed to solve the problem.
- For example, use the following problem to complete the organizer below.
- John collected 23 leaves on his walk on Monday. On Tuesday, he collected 35 leaves on his walk. At the end of his walk on Wednesday, he had collected a total of 97 leaves. How many leaves did he collect on Wednesday?
- What is this problem about? John collected leaves on Monday, Tuesday, and Wednesday.
- What do I know? John collected 23 leaves on Monday and 35 leaves on Tuesday. He has a total of 97 leaves.
- What is the problem asking? How many leaves did John collect Wednesday?
- Does this problem have one or two steps? This problem has 2 steps.
- What operation can I use to solve this problem? I can add and subtract.
- How can I model this problem to solve it? Students may use an equation, a drawing, or manipulatives to model their work.
- Teacher provides the chart/organizer below and guides students through determining if the start, change and result are known for each problem.
- Example:
- Instruction provides opportunities to determine the context of numberless word problems with a focus on what is happening in the problem and how to solve it.
- For example, the teacher provides the following word problem to students. Cindy Lou needs ___ cupcakes for the bake sale. She has already made ___ cupcakes. How many cupcakes does she still need to make? Teacher asks: What is this problem about? What is happening in this problem? What information do we know? How do you think you would solve this problem?
Instructional Tasks
Instructional Task 1(MTR.4.1)
A bus leaves Park Elementary School with 27 students. Twelve students get off at stop A and eight more get off at stop B. How many students are on the bus at stop C? [Teacher note: Discussion of student responses should allow the opportunity to make connections between varying strategies and discuss the efficiency of a chosen strategy.]
Instructional Items
Instructional Item 1
Mr. Gene sharpened 17 more pencils than Ms. Smith. Mr. Gene sharpened 32 pencils. How many pencils did Ms. Smith sharpen?
Instructional Item 2
Create a word problem that can be solved using the equation 76 = 11 + 65.
*The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.