Lesson 6

Thinking about Number Sentences

Est. Class Sessions: 2
X

Mathematical Standards

1.OA.A
Represent and solve problems involving addition and subtraction. (1.OA.A.1, 1.OA.A.2)
1.OA.B
Understand and apply properties of operations and the relationship between addition and subtraction. (1.OA.B.3)
1.OA.C
Add and subtract within 20.(1.OA.C.6)
1.OA.D
Work with addition and subtraction equations. (1.OA.D.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.
MP5.
Use appropriate tools strategically.
MP7.
Look for and make use of structure.

Students use a variety of methods to determine whether number sentences are true. They find missing numbers so that the expressions on both sides of the equal sign represent the same numerical value.

Content in this Lesson

  • Recognizing that the equal sign represents the relationship between two equal quantities [E4].
  • Representing addition and subtraction using drawings, counters, number sentences, number lines, or ten frames [E2].
  • Using strategies to solve addition problems with sums between 10 and 20 and the related subtraction problems [E5].
  • Using strategies that apply the properties of addition (e.g., turn-around, compose and decompose numbers) to solve addition and subtraction problems [E6].
  • Choosing good tools and an efficient strategy to solve a problem [MPE2].
  • Communicating mathematics verbally and in writing [MPE5].

Daily Practice and Problems Q–T

Q. Compare

R. Subtraction Facts

S. Time

T. Box Diagrams

X

Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Students Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Student Pairs

20 connecting cubes
desk number line (0–40)

Materials for the Teacher

Unit 12 Assessment Record
chart paper

Assessment in this Lesson

ASSESSMENT EXPECTATION ASSESSED MATH PRACTICES EXPECTATION ASSESSED
True or False
Check-In: Questions F–G Student Activity Book
Page 391
E4.
Recognize that the equal sign represents the relationship between two equal quantities.
MPE2.
Find a strategy. I choose good tools and an efficient 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.
Find the Missing Numbers
Check-In: Questions G–K Student Activity Book
Page 393
E4.
Recognize that the equal sign represents the relationship between two equal quantities.
E7.
Find the unknown whole number in an addition or subtraction equation relating three whole numbers.
MPE2.
Find a strategy. I choose good tools and an efficient 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.