Lesson 7

Addition and Subtraction: Practice and Estimation

Est. Class Sessions: 1
X

Mathematical Standards

3.NBT.A
Use place value understanding and properties of operations to perform multi-digit arithmetic. (3.NBT.A.1, 3.NBT.A.2)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason quantitatively.
MP4.
Model with mathematics.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.

A dime store provides the setting for practicing addition and subtraction. The word problems offer opportunities to estimate, find exact answers, and check for accuracy.

Content in this Lesson

  • Solving subtraction problems using base-ten pieces and number lines [E2].
  • Subtracting multidigit numbers using mental math strategies and paper-and-pencil methods [E3, E4].
  • Estimating differences using mental math strategies [E5].
  • Choosing appropriate mental math estimation and paper-and-pencil methods to subtract whole numbers.
  • Using mental math strategies to solve problems [MPE2].
  • Using benchmarks to estimate [MPE2].
  • Communicating mathematical reasoning [MPE5].
  • Checking the reasonableness of the solution [MPE3].

Daily Practice and Problems U–V

U. Using Subtraction

V. Twins and Triplets

X

Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Guide

Teacher Resources

 Teacher Guide - digital

Supplies for Students

desk number line (0–100)

Materials for the Teacher

chart paper, optional
Unit 7 Assessment Record

Assessment in this Lesson

Assessment Expectation Assessed Math Practice Assessed

Addition and Subtraction: Practice and Estimation
Check-In: Questions 7–8
Student Guide
Page 186
and corresponding Feedback Boxes
Teacher Guide - digital
E5.
Estimate differences using mental math strategies (e.g., rounding using benchmarks, using convenient numbers, composing and decomposing numbers, counting up and counting back).
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.

Vocabulary in this Lesson