In this Grade 4 lesson from enVision Mathematics Chapter 4, students learn how to multiply two-digit numbers using arrays and partial products by separating each factor into tens and ones. Using grid-based array models, they break a problem like 24 × 13 into four simpler multiplication facts — 20 × 10, 20 × 3, 4 × 10, and 4 × 3 — then add the partial products to find the final answer. Place-value concepts and the Commutative Property of Addition are applied throughout to build understanding of 2-digit by 2-digit multiplication.
Section 1
Representing Multiplication with an Array
To multiply two two-digit numbers, we can decompose each number into tens and ones and use the distributive property.
This can be visualized with an array, where the total area is the sum of four smaller areas, known as partial products.
For factors and :
Section 2
Recording Partial Products Vertically
To find the total product, the four partial products are recorded vertically, aligned by place value, and then added together.
Expand to review the lesson summary and core properties.
Section 1
Representing Multiplication with an Array
To multiply two two-digit numbers, we can decompose each number into tens and ones and use the distributive property.
This can be visualized with an array, where the total area is the sum of four smaller areas, known as partial products.
For factors and :
Section 2
Recording Partial Products Vertically
To find the total product, the four partial products are recorded vertically, aligned by place value, and then added together.