Lesson 3

Addition Strategies Seminar

Est. Class Sessions: 2
X

Mathematical Standards

2.OA.A
Represent and solve problems involving addition and subtraction. (2.OA.A.1)
2.OA.B
Add and subtract within 20. (2.OA.B.2)
2.MD.B
Relate addition and subtraction to length. (2.MD.B.6)
2.MD.C
Work with time and money. (2.MD.C.8)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason quantitatively.
MP3.
Construct viable arguments and critique the reasoning of others.
MP4.
Model with mathematics.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.
MP7.
Look for and make use of structure.
MP8.
Look for and express regularity in repeated reasoning.

Students participate in a "strategy session" to discuss using counting and reasoning strategies to solve addition problems with sums to 20. They build an Addition Strategies Menu for the Facts and discuss which strategies seem to be better suited for different addition facts. Students then practice using counting and reasoning strategies to solve addition problems.

Content in this Lesson

  • Representing addition situations using multiple representations (e.g., counters, number sentences, stories, number lines, ten frames) [E1].
  • Using mental math strategies and reasoning strategies (e.g., using doubles, making ten) to solve addition problems within 20 [E2].
  • Using addition to solve one-step word problems involving join situations [E3].
  • Analyzing the reasoning of others.
X

Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Book

 Student Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Students

20 connecting cubes

Materials for the Teacher

Display of Addition Strategies Menu for the Facts (Student Activity Book) Page 9
Display of Show Your Strategy Card Display Master (Teacher Guide)
Display of Here's What I Thought Master (Teacher Guide)
Prepared sets of Show Your Strategy Cards Masters (Teacher Guide). See Materials Preparation.
Unit 1 Assessment Record
connecting cubes
chart paper
tape

Materials Preparation

Prepare Strategy Charts. Display and write one of the following titles on each sheet of chart paper: "Counting Strategies" and "Reasoning Strategies." Leave these charts on display throughout the rest of the unit.

Prepare Show Your Strategy Cards. Make 18–20 copies of the Show Your Strategy Cards Master and cut them apart so you have 36–40 cards. Select addition facts from the list below and record a different fact on each card. See Figure 1. Keep the following cards separate to use for demonstration purposes at the beginning of the lesson: 6 + 1, 6 + 6, 6 + 7, and 9 + 5. Some of the addition facts from Groups A–C and all the facts from Groups D–F are included in the list:

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Figure 1: Prepared Show Your Strategy Card

TIMS Tip

If you have a small class, record only some of the addition problems. Choose facts that lend themselves to different counting and reasoning strategies.

Assessment in this Lesson

Assessment Expectation Assessed
How Did They Do It
Student Activity Book
Pages 13–14
E1.
Represent addition and subtraction situations using multiple representations (e.g., stories, drawings, counters, number sentences, number lines, diagrams, ten frames).
E2.
Use mental math strategies and reasoning strategies (e.g., using doubles, making ten) to solve addition and subtraction problems within 20.