Lesson 2

More Multiplication Stories

Est. Class Sessions: 2
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Mathematical Standards

3.OA.A
Represent and solve problems involving multiplication and division. (3.OA.A.3)
3.OA.B
Understand properties of multiplication and the relationship between multiplication and division. (3.OA.B.5)
3.OA.C
Multiply and divide within 100. (3.OA.C.7)
3.NBT.A
Use place value understanding and properties of operations to perform multidigit arithmetic. (3.NBT.A.3)

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.
MP7.
Look for and make sense of structure.

Students solve two-digit by one-digit multiplication problems. After exploring and discussing their own methods for solving these problems, they focus on the method of breaking apart products into the sum of simpler products. They pay particular attention to partitioning numbers into tens and ones. Then they write stories to represent the multiplication problems and refine the stories to reflect their partitions. This work leads to the development of a paper-and-pencil algorithm for multiplication.

Content in this Lesson

  • Representing 2-digit by 1-digit multiplication problems using drawings, stories, and number sentences [E1].
  • Showing connections between models and strategies for multiplication [E2].
  • Solving multidigit multiplication problems using mental math strategies (e.g., decomposing numbers and halving) [E3].
  • Solving multiplication problems by breaking products into the sum of simpler products (applying the distributive property of multiplication over addition) using the all-partials paper-and-pencil method [E7].
  • Multiplying one-digit whole numbers by multiples of ten [E5].
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Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Guide
Student Activity Book

Teacher Resources

 Teacher Guide - digital

Materials for the Teacher

Display of Roberto's Chart Master (Teacher Guide) Page 92
Unit 13 Assessment Record

Materials Preparation

Triangle Flash Cards. The Triangle Flash Cards for all the multiplication fact groups were provided and distributed in Units 8–12. If needed, prepare copies of the Triangle Flash Cards on heavier paper or card stock. Have students cut apart each set and store them in an envelope. You may want to provide each student with two sets, one to use at school and one to take home.

Assessment in this Lesson

Assessment Expectation Assessed Math Practices Expectation Assessed

Roberto's Charts
Check-In: Question 5
with Feedback Box
Student Activity Book
Pages 527–528
E1.
Represent 2-digit by 1-digit multiplication and multidigit division problems using counters, tiles, rectangular arrays, drawings, stories, and number sentences.
E2.
Show connections between models and strategies for multiplication (e.g., demonstrate partial products using a rectangle model for multiplication).
E3.
Solve multidigit multiplication problems using mental math strategies (e.g., composing and decomposing numbers, and doubling and halving).
E5.
Multiply one-digit whole numbers by multiples of ten.
E7.
Solve multiplication problems by breaking products into the sum of simpler products (applying the distributive property of multiplication over addition) using a rectangle model and paper-and-pencil methods (e.g., all-partials).
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.

Home Practice Part 1
Triangle Flash Cards: Review All Facts
Teacher Guide - digital
E16.
Demonstrate fluency with all the multiplication facts.