Lesson 2

All-Partials Revisited

Est. Class Sessions: 2
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Mathematics Standards

4.NBT.A
Generalize place value understanding for multi-digit whole numbers. (4.NBT.A.1, 4.NBT.A.2, 4.NBT.A.3)
4.NBT.B
Use place value understanding and properties of operaitons to perform multi-digit arithmetic. (4.NBT.B.5)
4.OA.A
Use the four operations with whole numbers to solve problems. (4.OA.A.3)
4.MD.A
Solve problems involing measurement and conversions of measurements from a larger unit to a smaller unit. (4.MD.A.3)

Standards for Mathematical Practice

MP2.
Reason quantitatively.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.
MP7.
Look for and make sense of structure.

Students explore another paper-and-pencil method for multiplication of 2-digit by 2-digit numbers—the all-partials method. They compare this method to using the rectangle model and expanded form. All three methods rely on breaking the numbers into tens and ones and using the distributive property to find partial products.

Content in this Lesson

  • Multiplying numbers that are multiples of ten.
  • Showing understanding of place value concepts by using the distributive property to multiply [E1].
  • Making connections between the rectangle model of multiplication, the expanded form, and the all-partials method [E2].
  • Estimating products of 2-digit numbers and explaining one's reasoning [E3].
  • Multiplying 2-digit by 2-digit numbers using mental math strategies, rectangle models, expanded form, and the all-partials method [E4].
  • Choosing appropriate multiplication strategies [E6].
  • Checking the reasonableness of a solution [MPE3].
  • Communicating solution strategies verbally and in writing [MPE5].
  • Identifying the important information in a problem [MPE1].
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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

Unit 11 Assessment Record

Assessment in this Lesson

Assessment Expectation Assessed Math Practices
Expectation Assessed
All-Partials Revisited
Check-In: Question 18
Student Guide
Page 496
and corresponding Feedback Box
Teacher Guide - digital
E2.
Show connections between models and strategies for multiplying 2-digit by 2-digit numbers (e.g., demonstrate partial products
using a rectangle model for multiplication).
E4.
Multiply 2-digit by 2-digit numbers using mental math strategies and paper-and-pencil methods (e.g., expanded form, all-partials).
MPE1.
Know the problem. I read the problem carefully. I know the questions to answer and what information is important.
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.
Multiplication Quiz 1 with Feedback Box
Teacher Guide - digital
E1.
Demonstrate understanding of the place value concepts and mathematical properties involved in multiplication of 2-digit by 2-digit numbers (e.g., use the distributive property to multiply).
E3.
Estimate products of multidigit numbers.
E4.
Multiply 2-digit by 2-digit numbers using mental math strategies and paper-and-pencil methods (e.g., expanded form, all-partials).
E6.
Choose appropriately from among estimation, mental math strategies, and paper-and-pencil methods to multiply multidigit numbers.

Vocabulary in this Lesson