Lesson 8

Use Math Strategies to Solve Problems

Est. Class Sessions: 1
X

Mathematical Standards

1.OA.A
Represent and solve problems involving addition and subtraction. (1.OA.A.1, 1.OA.A.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.
MP6.
Attend to precision.

Students solve addition and subtraction problems while focusing on the important information in the problem, finding a strategy, showing their work, and checking for reasonableness. They encounter a range of different kinds of addition and subtraction problems including multi-step problems.

Content in this Lesson

  • Representing addition and subtraction using number sentences [E3].
  • Solving addition and subtraction problems involving multiples of ten [E7].
  • Knowing what is important to solve a problem [MPE1].
  • Finding addition and subtraction strategies to solve problems [MPE2].
  • Checking for reasonableness [MPE3].
  • Showing how to solve problems [MPE5].

Daily Practice and Problems U–V

U. Fact Families: Group D

V. Compare Numbers

X

Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Students

20 connecting cubes
desk number line (0–40)

Materials for the Teacher

Display of Math Practices (Student Activity Book) Reference
Display of Professor Peabody's Problem Master (Teacher Guide)
Unit 11 Assessment Record
Math Facts Class Record
Unit 11 Individual Assessment Record
10 trains of connecting cubes, 10 cubes each. See Materials Preparation.
class number line (0–130)
word problem chart. See Materials Preparation.

Materials Preparation

Prepare a Display of Word Problems. Write the following problems on chart paper:

  1. Maria had 40 marbles. Then she found more marbles. When she counted all the marbles, she had 60 marbles. How many did she find?
  2. Maria had some marbles in a bag. She added 20 marbles to the bag and then she had 30 marbles. How many did she have before she added the 20 marbles to the bag?
  3. Tony had 60 marbles. He sold 40 marbles. Later he sold 10 more. How many marbles does he have left?

Prepare Trains of Connecting Cubes. Build 10 trains of connecting cubes with 10 cubes each.

Assessment in this Lesson

Assessment Expectation Assessed Math Practices Expectation Assessed
Problem Solving with
Bags of Marbles
with Feedback Box
Student Activity Book
Pages 357–358
E3.
Represent addition and subtraction using number sentences.
E7.
Solve addition and subtraction problems involving multiples of ten using links, coins, ten frames, and the 100 Chart.
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.
DPP Item U
Fact Families: Group D
Teacher Guide - digital
E13.
Determine the unknown number in an addition or subtraction sentence relating three whole numbers for the facts with sums to ten in Group D.

Vocabulary in this Lesson