In this Grade 4 Eureka Math lesson, students learn how to transition from using four partial products to two partial products when solving two-digit by two-digit multiplication problems like 26 × 35. Using area models, students connect the partial product method to the standard multiplication algorithm by grouping and combining partial products. This lesson builds the conceptual foundation needed to apply the standard algorithm for two-digit by two-digit multiplication covered in Chapter 16.
Section 1
Grouping Partial Products from an Area Model
The four partial products from an area model can be grouped to form two partial products. This grouping combines the products related to the ones digit and the products related to the tens digit of one of the factors. For a problem like :
Section 2
Concept: Decomposing into Partial Products
To multiply two two-digit numbers, you can decompose one number into its tens and ones.
Multiply each part by the second number to get two partial products, then add them together.
For two numbers and , where :
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter
Expand to review the lesson summary and core properties.
Section 1
Grouping Partial Products from an Area Model
The four partial products from an area model can be grouped to form two partial products. This grouping combines the products related to the ones digit and the products related to the tens digit of one of the factors. For a problem like :
Section 2
Concept: Decomposing into Partial Products
To multiply two two-digit numbers, you can decompose one number into its tens and ones.
Multiply each part by the second number to get two partial products, then add them together.
For two numbers and , where :
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter