Lesson 4

Subtraction with Base-Ten Pieces

Est. Class Sessions: 2
X

Mathematical Standards

2.NBT.A
Understand place value. (2.NBT.A.1)
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)

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.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.

Students partition a number in different ways while solving subtraction problems with base-ten pieces. This helps them develop a concrete understanding of the trading involved in subtraction in preparation for their work with paper-and-pencil algorithms.

Content in this Lesson

  • Estimating differences using mental math strategies (e.g., rounding using benchmarks, using friendly numbers, composing and decomposing numbers, counting on) [E5].
  • Determining the reasonableness of a solution to a subtraction problem [MPE3].
  • Solving a problem another way to check calculations [MPE4].
  • Representing multidigit subtraction problems using base-ten pieces [E2].
  • Subtracting multidigit numbers using mental math strategies (e.g., composing and decomposing numbers, counting up) with number lines, 200 Charts, and base-ten pieces [E3].
  • Using and applying place value concepts to make connections among representations of numbers [E1].
X

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, 5 flats)
desk number line (0–100)

Materials for the Teacher

Display of Math Practices (Student Activity Book) Reference
Unit 9 Assessment Record
Math Facts Class Record
Display set of base-ten pieces
Subtraction Strategies Chart from Lesson 2

Assessment in this Lesson

ASSESSMENT EXPECTATION ASSESSED MATH PRACTICES EXPECTATION ASSESSED
Subtract with Base-Ten Pieces
Check-In: Question 6
Student Activity Book
Page 454
E2.
Represent subtraction problems using base-ten pieces and number lines.
E3.
Subtract multidigit numbers using mental math strategies (e.g., composing and decomposing numbers, counting up) with number lines,
a 200 Chart, and base-ten pieces.
E5.
Estimate differences using mental math strategies (e.g., rounding using bench marks, using friendly numbers, compoing and decomposing numbers, counting on).
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.
DPP Item L
Fact Families
Teacher Guide - digital
E7.
Determine the unknown number in an addition or subtraction sentence relating three whole numbers for the facts in Group A.