﻿ Gr. 2 Represent & Solve Problems Involving Addition & Subtraction ~ Math Units of Study ~ Instruction ~ School Improvement in Maryland

# Gr. 2 Unit: Represent & Solve Problems Involving Addition & Subtraction

### Lesson Seeds

Send Feedback to MSDE’s Mathematics Team

##### Unit Overview

In this unit, students continue to expand their understanding of addition and subtraction from their work in Kindergarten and Grade 1. In Grade 1 students solved word problems within 20. They now extend that ability to use addition and subtraction within 100 to solve one- and two-step problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all position. This is the first time they will have dealt with two-step problems. As in Grade 1, they will use drawings and equations with a symbol for the unknown number to represent the problem. It is in second grade that students will be expected to master all types of problems as listed above, including the more difficult problem types introduced in Grade 1.

Essential Questions:

• Why do I need mathematical operations?
• How do mathematical operations relate to each other?
• How do I know which mathematical operation (+, -) to use?
• How do I decide which representation to use when solving problems (concrete manipulatives, pictures, words, or equations)?
• How do I know which computational method (mental math, estimation, paper and pencil, and calculator) to use?
• What is meant by equality in mathematics?
• How do I know where to begin when solving a problem?
• How does explaining my process help me to understand a problem’s solution better?
• How do I decide what strategy will work best in a given problem situation?
• What do I do when I get stuck?
• How do I know when a result is reasonable?
• What is the relationship between solving problems and computation?
• Why is the ability to solve problems the heart of mathematics?
• What are efficient methods for finding sums and differences?

A question is essential when it stimulates multi-layered inquiry, provokes deep thought and lively discussion, requires students to consider alternatives and justify their reasoning, encourges re-thinking of big ideas, makes meaningful connections with prior learning, and provides students with opportunities to apply problem-solving skills to authentic situations.

##### Unit Lesson

Additional information such as Teachers Notes, Enduring Understandings,Content Emphasis by Cluster, Focus Standards, Possible Student Outcomes, Essential Skills and Knowledge Statements and Clarifications, and Interdisciplinary Connections can be found in this Lesson Unit.

##### Available Model Lesson Plans

The lesson plan(s) have been written with specific standards in mind. Each model lesson plan is only a MODEL - one way the lesson could be developed. We have NOT included any references to the timing associated with delivering this model. Each teacher will need to make decisions related ot the timing of the lesson plan based on the learning needs of students in the class. The model lesson plans are designed to generate evidence of student understanding.

This chart indicates one or more lesson plans which have been developed for this unit. Lesson plans are being written and posted on the Curriculum Management System as they are completed. Please check back periodically for additional postings.

CCSC Alignment: 2.OA.A.1

Students work in small groups to create addition problems from real life situations and stories. They justify and model their solutions using place value blocks. Student also discuss the possible strategies that could be used to solve the problems.

##### Available Model Lesson Seeds

The lesson seed(s) have been written with specific standards in mind. These suggested activity/activities are not intended to be prescriptive, exhaustive, or sequential; they simply demonstrate how specific content can be used to help students learn the skills described in the standards. Seeds are designed to give teachers ideas for developing their own activities in order to generate evidence of student understanding.

This chart indicates one or more lesson seeds which have been developed for this unit. Lesson seeds are being written and posted on the Curriculum Management System as they are completed. Please check back periodically for additional postings.

CCSC Alignnment: 2.OA.A.1

Students move around the Hundred Chart to solve problems and share their solutions.

CCSC Alignnment: 2.OA.A.1

Students use an open number line to solve addition and subtraction word problems