Demonstrate the commutativity of multiplication.
Students need not use formal terms for the properties of operations, including the terms “commutative” or “commutative property.” However, exposure to the term is helpful so that students can develop and use a common language and thus is introduced in this lesson.
1. Mr. Barron is working with a small group of students. He sets up their seats facing the whiteboard into two rows with three chairs in each row.
a. Draw the seats in Mr. Barron’s room below, using squares to represent the seats.
b. Write a multiplication equation that can be used to find the total number of seats Mr. Barron has in the room.
c. Determine the total number of seats in Mr. Barron’s room.
2. Sometimes Mr. Barron wants to use chart paper on the side of his room, which you can see in the diagram above. Imagine students facing Mr. Barron at the chart paper.
a. Write a multiplication equation that can be used to find the total number of seats Mr. Barron has in the room.
b. Determine the total number of seats in Mr. Barron’s room.
3. What do you notice about #1 and #2? What do you wonder?
Is the following statement true or false? Explain your answer.
$$4 \times 5 = 5\times 4$$
a. $$2\times 8 = $$ _____
b. _____ $$= 10\times 7$$
|$$2\times 5 = 5\times 2$$|
Do you agree or disagree with the statement in the box? Draw a picture to explain your answer.
Grade 3 Mathematics > Module 1 > Topic C > Lesson 7 of the New York State Common Core Mathematics Curriculum from EngageNY and Great Minds. © 2015 Great Minds. Licensed by EngageNY of the New York State Education Department under the CC BY-NC-SA 3.0 US license. Accessed Dec. 2, 2016, 5:15 p.m..Modified by The Match Foundation, Inc.