Lesson 3

Adding Multidigit Numbers

Est. 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.7, 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)
2.OA.D
Add and subtract within 20. (2.OA.B.2)

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 make connections among representations and a variety of mental math and paper-and-pencil strategies as they solve multidigit addition problems with sums through one thousand. They practice estimating sums, and using expanded form, all-partials, and the compact method.

Content in this Lesson

  • Using and applying place value concepts to make connections among representations of multidigit numbers using base-ten pieces, number lines, expanded form, and standard form [E1].
  • Composing and decomposing numbers using ones, tens, hundreds, and thousands [E2].
  • Showing different partitions of numbers (to 1000) using different representations (e.g., base-ten pieces, number lines, number sentences) [E3].
  • Representing addition problems using base-ten pieces and number lines [E5].
  • Adding multidigit numbers using mental math strategies (e.g., composing and decomposing numbers, counting) with base-ten pieces and number lines [E6].
  • Adding multidigit numbers using paper-and-pencil methods (e.g., expanded form, all-partials, compact) [E7].
  • Estimating sums using mental math strategies (e.g., rounding using benchmarks, using friendly numbers, composing and decomposing numbers, counting) [E8].
  • Knowing what is important when solving a problem [MPE1].
  • Finding an efficient strategy for solving a problem [MPE2].
  • Using estimation to check for reasonableness [MPE3].
  • Solving a problem a second way to check [MPE4].
  • Showing or telling how to solve a problem [MPE5].
  • Using labels to show what numbers mean [MPE6].
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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

set of base-ten pieces (2 packs, 11 flats, 20 skinnies, 21 bits)

Supplies for Student Pairs

chart paper

Materials for the Teacher

Display of Addition Strategies Menu (Student Activity Book) Reference
Display of Help Her Fix It (Student Activity Book) Pages 733–734
Display of Math Practices (Student Activity Book) Reference
Unit 14 Assessment Record
Display set of base-ten pieces (2 packs, 11 flats, 20 skinnies, 21 bits)
chart paper

Assessment in this Lesson

Assessment Expectation Assessed Math Practices Expectation Assessed
Finish It: Addition
Check-In: Questions 2–6
with Feedback Box
Student Activity Book
Pages 730–731
E1. 
Use and apply place value concepts to make connections among representations of multidigit numbers using base-ten pieces, number lines, expanded form, and standard form.
E6. 
Add and subtract multidigit numbers using mental math strategies (e.g., composing and decomposing numbers, counting) with base-ten pieces and number lines.
E7. 
Add and subtract multidigit numbers using paper-and-pencil methods (e.g., expanded form, all-partials, compact).
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.
Shark Day
Check-In: Questions 4–5
with Feedback Box
Student Activity Book
Pages 737–738
E6. 
Add and subtract multidigit numbers using mental math strategies (e.g., composing and decomposing numbers, counting) with base-ten pieces and number lines.
E7. 
Add and subtract multidigit numbers using paper-and-pencil methods (e.g., expanded form, all-partials, compact).
E8. 
Estimate sums and differences using mental math strategies (e.g., rounding using benchmarks, using friendly numbers, composing and decomposing numbers, counting).
MPE1. 
Know the problem. I read the problem carefully. I know the questions to answer and what information is important.
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.
MPE5. 
Show my work. I show or tell how I arrived at my answer so someone else can understand my thinking.
MPE6. 
Use labels. I use labels to show what numbers mean.
My Own Addition Strategies Menu
Student Activity Book
Page 739
E6. 
Add and subtract multidigit numbers using mental math strategies (e.g., composing and decomposing numbers, counting) with base-ten pieces and number lines.
E7. 
Add and subtract multidigit numbers using paper-and-pencil methods (e.g., expanded form, all-partials, compact).
MPE4. 
Check my calculations. If I make mistakes, I correct them.
MPE5. 
Show my work. I show or tell how I arrived at my answer so someone else can understand my thinking.