Lesson 3

Multiplication Models and Strategies

Est. Class Sessions: 2
X

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 multdigit 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.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.
MP7.
Look for and make sense of structure.

Students are introduced to the all-partials algorithm for multiplication. They show connections between rectangle models and this new partial-product strategy to strengthen understanding of the meaning behind the notations they make. Students practice using the method to multiply and to check whether their answers are reasonable.

Content in this Lesson

  • Representing 2-digit by 1-digit multiplication problems using rectangular arrays and number sentences [E1].
  • Showing connections between rectangle models and partial-product strategies for multiplication [E2].
  • 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].
  • Solving multidigit multiplication problems using mental math strategies (e.g., decomposing numbers and halving) [E3].
  • Multiplying one-digit whole numbers by multiples of ten [E5].
X

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 Professor Peabody's Hallway Master (Teacher Guide)
Display of Rectangle Models Master (Teacher Guide)
Display of Half-Centimeter Grid Paper Master (Teacher Guide) optional
Unit 13 Assessment Record

Materials Preparation

Gather Materials for Targeted Practice. Place copies of Roberto's Chart Master from Lesson 2 and the Half-Centimeter Grid Paper Master in a center. Ask students to write multiplication stories and to represent the stories and solutions with rectangular arrays.

Assessment in this Lesson

Assessment Expectation Assessed Math Practices Expectation Assessed

Solving Problems Mara's Way
Check-In: Questions 3–8
with Feedback Box
Student Activity Book
Pages 532–535
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).
MPE3.
Check for reasonableness. I look back at my solution to see if my answer makes sense. If it does not, I try again.