Lesson 8

Solve Word Problems

Est. Class Sessions: 3
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Mathematical Standards

2.OA.A
Represent and solve problems involving addition and subtraction. (2.OA.A.1)
2.OA.B
Add and subtract within 20. (2.OA.B.2)
2.MD.B
Relate addition and subtraction to length. (2.MD.B.6)
2.MD.C
Work with time and money. (2.MD.C.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.
MP4.
Model with mathematics.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.
MP8.
Look for and express regularity in repeated reasoning.

Students learn how to represent addition and subtraction problems with drawings, connecting cubes, number lines, ten frames, and part-whole diagrams. They also develop strategies for getting to know a word problem while solving problems that involve join, separate/take away, part-whole or compare situations.

Content in this Lesson

  • Representing addition and subtraction situations using multiple representations (e.g., counters, number sentences, number lines, drawings, part-whole diagrams, ten frames) [E1].
  • Using mental math strategies and reasoning strategies (e.g., using doubles, making ten) to solve addition and subtraction problems within 20 [E2].
  • Using addition and subtraction to solve one-step word problems involving join, separate/take away, part-whole, and compare situations [E3].
  • Solving word problems involving cents.
  • Knowing what is important to solve a problem [MPE1].
  • Finding addition and subtraction strategies to solve problems [MPE2].
  • Showing or telling how to solve problems [MPE5].
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Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Book

 Student Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Students

20 connecting cubes

Supplies for Student Pairs

scissors
tape or glue stick
markers

Materials for the Teacher

8 display copies of the Show a Word Problem Master (Teacher Guide)
Display of Math Practices (Student Activity Book) Reference
Display of the first page of Animal Trading Cards (Student Activity Book) Page 49
Animal Trading Cards Master (Teacher Guide), optional. See Materials Preparation.
Copies of Show a Word Problem Master (Teacher Guide), optional. See Materials Preparation.
Unit 1 Assessment Record
20 connecting cubes
chart paper
A Cache of Jewels and Other Collective Nouns by Ruth Heller, optional

Materials Preparation

Prepare Display of Problems. Write the following four problems in the box on copies of the Show a Word Problem Master. The first two problems will be used in Part 1 and the last two will be used in Part 2.

  • There are 8 lions and 4 monkeys at the zoo. How many animals are there altogether?
  • There are 11 fish in a bowl. Five of the fish are orange and the rest are green. How many are green?
  • There is a colony of penguins. Four baby penguins are born. Now there are 13 penguins. How many penguins were in the colony before the babies were born?
  • A litter of puppies has 11 brown puppies. Another litter has 9 black puppies. How many more brown puppies are there than black puppies?

Prepare Problems on Chart Paper. Write one problem for each pair of students on sheets of chart paper. Problems can be repeated, if needed. Prepare space to display these problems, too.

  • There were 7 monkeys and some joined them. Now there are 12 monkeys. How many joined them?
  • There was a swarm of 15 bees in a tree. Eight of them flew away. How many are left in the tree?
  • There are 14 fish in an aquarium. Five of the fish are orange and the rest are yellow. How many fish are yellow?
  • One pack of wolves has 9 wolves. Another pack has 4 more than the first pack. How many wolves does the second pack have?
  • There are 5 catfish and 2 small sharks in the aquarium. How many more catfish are there than sharks?
  • A herd of elephants is visiting a pond. Eight more join them. There are now 16 elephants at the pond. How many were at the pond earlier?

Prepare Optional Targeted Practice. Place a few of the chart paper displays students made during the lesson, copies of the Show a Word Problem Master, and a copy of the Animal Trading Cards Master in a learning center. Ask students to write and then solve their own problems. Challenge students to write different types of problems and solve each problem in more than one way. They can use the problems and solutions displayed as inspiration.

Assessment in this Lesson

Assessment Expectation Assessed Math Practices Expectation Assessed
Trading Card Problems
with Feedback Box
Student Activity Book
Pages 55–58
E1. 
Represent addition and subtraction situations using multiple representations (e.g., stories, drawings, counters, number sentences, number lines, diagrams, ten frames).
E2. 
Use mental math strategies and reasoning strategies (e.g., using doubles, making ten) to solve addition and subtraction problems within 20.
E3. 
Use addition and subtraction to solve one- and two-step word problems involving join, separate/take away, part-whole, and compare situations.
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.
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