Lesson 7

Workshop: Addition Strategies

Estimated Class Sessions: 2–3
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Mathematical Standards

2.NBT.A
Understand place value. (2.NBT.A.1, 2.NBT.A.2)
2.NBT.B
Use place value understanding and properties of operations to add and subtract. (2.NBT.B.6, 2.NBT.B.8, 2.NBT.B.9)
2.MD.B
Relate addition and subtraction to length. (2.MD.B.6)
2.OA.A
Represent and solve problems involving addition and subtraction. (2.OA.A.1)

Standards for Mathematical Practice

MP2.
Reason quantitatively.
MP6.
Attend to precision.

Students practice a variety of mental math and paper-and-pencil addition methods with two-digit and three-digit numbers. They estimate and check for reasonableness, and explore the efficiency and usefulness of the strategies in various situations.

Content in this Lesson

  • Using and applying place value concepts to make connections among representations of numbers [E1].
  • Solving two-digit and three-digit addition problems using mental math
    strategies [E3].
  • Solving two-digit and three-digit addition problems using paper-and-pencil methods [E4].
  • Estimating sums using mental math strategies [E6].
  • Choosing good tools and efficient strategies for solving problems [MPE2].
  • Determining the reasonableness of a solution to an addition problem [MPE3].
  • Checking calculations [MPE4].
  • Communicating solution strategies and reasoning [MPE5].
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Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Students

base-ten pieces (21 bits, 20 skinnies, and 3–5 flats)
desk number line (0–100)
Addition Strategies Menu from Lesson 6

Materials for the Teacher

Display of Addition Strategies Menu (Student Activity Book) Reference
Display of Addition Strategies Workshop Menu (Student Activity Book) Page 357
Display of Add to 100 Game Master (Teacher Guide)
Display of the first page of the Path to Glory Game from the Mental Math Games pages (Student Activity Book) Page 365
Display of Math Practices (Student Activity Book) Reference
2 prepared display sets of digit cards from Digit Cards 0–9 Master (Teacher Guide). See Materials Preparation.
Unit 7 Assessment Record
class number line (0–130)

Materials Preparation

Prepare Digit Cards. Make copies of the Digit Cards 0–9 Masters and cut out the cards. You will need 4 prepared display sets of digit cards to demonstrate the Add to 100 Game. You will also need 4 sets of cards per pair for this game during the Workshop. If you are setting up centers, decide how many students may play at one time and have an appropriate number of sets of digit cards ready. Your display sets can be placed in the center for student use after the demonstration of the game. Save these sets of prepared cards for games in future units.

Assessment in this Lesson

ASSESSMENT EXPECTATION ASSESSED MATH PRACTICES EXPECTATION ASSESSED
Addition Strategies Workshop Menu
Self-Check
Student Activity Book
Page 357
E1.
Use and apply place value concepts to make connections among representations of numbers to the thousands using base-ten pieces, number lines, expanded form, and standard form.
E3.
Add two-digit and three-digit numbers using mental math strategies (e.g., composing and decomposing numbers, counting on) using the 200 Chart, base-ten pieces, and number lines.
E4.
Add two-digit and three-digit numbers using paper-and-pencil methods (e.g., expanded form, all-partials, compact).
Addition Strategies Quiz
With Feedback Box
Student Activity Book
Pages 369–371
E1.
Use and apply place value concepts to make connections among representations of numbers to the thousands using base-ten pieces, number lines, expanded form, and standard form.
E3.
Add two-digit and three-digit numbers using mental math strategies (e.g., composing and decomposing numbers, counting on) using the 200 Chart, base-ten pieces, and number lines.
E4.
Add two-digit and three-digit numbers using paper-and-pencil methods (e.g., expanded form, all-partials, compact).
E6.
Estimate sums using mental math strategies (e.g., rounding using benchmarks, using friendly numbers, composing and decomposing numbers, counting on).
MPE2. 
Find a strategy. I choose good tools and an efficient strategy for solving the problem.
MPE3. 
Check for reasonableness. I look back at my solution to see if my answer makes sense. If it does not, I try again.
MPE4. 
Check my calculations. If I make mistakes, I correct them strategy for solving the problem.
MPE5. 
Show my work. I show or tell how I arrived at my answer so someone else can understand my thinking.