Lesson 9

Paper-and-Pencil Multiplication

Est. Class Sessions: 2–3
X

Mathematical Standards

4.NBT.A
Generalize place value understanding for multi-digit whole numbers. (4.NBT.A.2)
4.NBT.B
Use place value understanding and properties of operations to perform multi-digit arithmetic. (4.NBT.B.5)

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.
MP6.
Attend to precision.
MP7.
Look for and make use of structure.

Two commonly used methods for recording work while solving multiplication problems are presented: the all-partials method and the compact method (the United States' traditional multiplication algorithm). Both involve breaking numbers into their base-ten parts and multiplying the parts. The problems in the lesson involve 1-digit by 2-digit multiplication.

Content in this Lesson

  • Multiplying 2-digit numbers by 1-digit numbers using paper-and-pencil methods (all-partials and compact) [E8].
  • Choosing appropriately from among mental math and paper-and-pencil methods to multiply whole numbers [E10].
X

Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Guide

Teacher Resources

 Teacher Guide - digital

Materials for the Teacher

Display of the multiplication strategy charts from Lesson 8. See Materials Preparation.
Unit 4 Assessment Record
Math Facts Class Record
chart paper

Materials Preparation

Strategy Charts. In Lesson 8, students prepared a collection of charts that named and displayed a variety of mental math and paper-and-pencil methods to multiply. Display these charts so students can compare these strategies in this lesson. You will add one strategy and one more chart to this collection in this lesson.

Assessment in this Lesson

Assessment Expectation Assessed
Paper-and-Pencil Multiplication
Questions 9–11
Student Guide
Page 160
E5.
Solve multiplication problems using mental math strategies (e.g., composing and decomposing numbers and doubling and halving).
E8.
Multiply 2-digit numbers by 1-digit numbers using paper-and-pencil methods (expanded form, all-partials, compact).
E10.
Choose appropriately from among mental math and paper-and-pencil methods to multiply whole numbers.
DPP Item GG
Multiplication Quiz: 9s
Teacher Guide - digital
E12.
Demonstrate fluency with the multiplication facts for the 2s, 3s, and 9s.
DPP Item HH
Finding n
Teacher Guide - digital
E1.
Show that different partitions of the same number are equal using base-ten pieces, number lines, and number sentences (e.g., 200 + 30 + 7 = 200 + 20 + 17).