### Clarifications

*Clarification 1:*Instruction includes understanding the context of the problem, as well as the quantities within the problem.

*Clarification 2:* Problems include creating real-world situations based on an equation.

*Clarification 3:* Addition and subtraction are limited to sums up to 100 and related differences. Refer to Situations Involving Operations with Numbers (Appendix A).

**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)

### Instructional Items

*Instructional Item 1*

*Instructional Item 2*

**The strategies, tasks and items included in the B1G-M are examples and should not be considered comprehensive.*

## Related Courses

## Related Access Points

## Related Resources

## Formative Assessments

## Lesson Plans

## Problem-Solving Task

## Tutorials

## STEM Lessons - Model Eliciting Activity

In this Model Eliciting Activity, MEA, students will help the Sweet Donut Shop determine what the newest donut will be. Students are given the cost to make each batch along with the selling price and are asked to determine the profit for each batch. Students create a procedure for ranking the donuts and write a letter explaining the procedure and the ranking. In the “twist” students are provided the starting and finishing times for each batch. They must determine the total amount of time, decide if their procedure should change based on the new information, and write a letter explaining whether the procedure changed and the new ranking of the donuts.

Model Eliciting Activities, MEAs, are open-ended, interdisciplinary problem-solving activities that are meant to reveal students’ thinking about the concepts embedded in realistic situations. MEAs resemble engineering problems and encourage students to create solutions in the form of mathematical and scientific models. Students work in teams to apply their knowledge of science and mathematics to solve an open-ended problem, while considering constraints and tradeoffs. Students integrate their ELA skills into MEAs as they are asked to clearly document their thought process. MEAs follow a problem-based, student centered approach to learning, where students are encouraged to grapple with the problem while the teacher acts as a facilitator. To learn more about MEA’s visit: https://www.cpalms.org/cpalms/mea.aspx

## MFAS Formative Assessments

Students are asked to solve two word problems: Add To (Start Unknown) and Take From (Start Unknown).

Students are asked to solve a Put Together/Take Apart (Both Addends Unknown) word problem and explain their strategies.

Students are asked to solve two Compare (Bigger Unknown) word problems: one involving the word more and one involving the word fewer.

Students are asked to solve two Compare (Smaller Unknown) word problems: one involving the word more and one involving the word fewer.

Students are asked to solve two Compare (Difference Unknown) word problems: a *how many more* and a *how many fewer* variation.

Students are asked to solve three word problems: Put Together (Addend Unknown), Take From (Change Unknown), Add to (Change Unknown).

Students are asked to solve a two-step word problem that combines a Compare (Bigger Unknown) problem and a Compare (Smaller Unknown) problem.

Students are asked to solve a two-step word problem that combines an Add To (Result Unknown) problem and a Compare (Difference Unknown) problem.

Students are asked to solve a two-step word problem that combines a Put Together (Result Unknown) problem and a Take FromĀ (Result Unknown) problem.

Students are asked to solve three word problems: Add To (Result Unknown), Take From (Result Unknown), and Put Together/Take Apart (Total Unknown).

## Student Resources

## Problem-Solving Task

This task could be used for either instructional or assessment purposes, depending on where students are in their understanding of addition and how the teacher supports them. The solution shown is very terse; students' solution strategies are likely to be much more varied.

Type: Problem-Solving Task

## Tutorials

In this tutorial you will learn how to solve a word problem by creating a chart and adding the same number many times.

Type: Tutorial

This Khan Academy tutorial, called, "sports on a die" explains the pitfalls of relying on key words in a word problem. Students solve a problem by writing a missing addend addition equation and solve with the standard algorithm for subtracting two digit numbers.

Type: Tutorial

In this tutorial video from Khan Academy, called "Using crayons", explore subtracting within 100 using the standard algorithm, as well as a bar diagram.

Type: Tutorial

In this video tutorial from Khan Academy called "losing tennis balls", explore solving a two-step subtraction word problem using the standard algorithm.

Type: Tutorial

In this tutorial video from Khan Academy, called "Fence posts for horses", explore adding a two digit number to a two digit number using the standard algorithm

Type: Tutorial

In this video tutorial from Khan Academy, explore using a number line solve word problems involving more than two numbers.

Type: Tutorial

## Parent Resources

## Problem-Solving Task

This task could be used for either instructional or assessment purposes, depending on where students are in their understanding of addition and how the teacher supports them. The solution shown is very terse; students' solution strategies are likely to be much more varied.

Type: Problem-Solving Task

## Tutorials

This Khan Academy tutorial, called, "sports on a die" explains the pitfalls of relying on key words in a word problem. Students solve a problem by writing a missing addend addition equation and solve with the standard algorithm for subtracting two digit numbers.

Type: Tutorial

In this tutorial video from Khan Academy, called "Using crayons", explore subtracting within 100 using the standard algorithm, as well as a bar diagram.

Type: Tutorial

In this video tutorial from Khan Academy called "losing tennis balls", explore solving a two-step subtraction word problem using the standard algorithm.

Type: Tutorial

In this tutorial video from Khan Academy, called "Fence posts for horses", explore adding a two digit number to a two digit number using the standard algorithm

Type: Tutorial

In this video tutorial from Khan Academy, explore using a number line solve word problems involving more than two numbers.

Type: Tutorial