Multiplication Properties

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Objective

SWBAT use multiplication properties (such as the commutative property or the property of one) to simplify computations.

Big Idea

Multiplication Properties are rules that can be used to help with math computation.

Do Now

10 minutes

When students enter the classroom I have the "Do Now" on the board. I give each student 3 index cards with instructions to write the vocabulary word on the front and the definition on the back of the cards.  After copying down the vocabulary I give the class about 5 minutes to study the vocabulary words with a partner.

Whole Class

10 minutes

Rationale for teaching this lesson:  I feel that it is important for the students to know the multiplication properties because they will help the students with computation.  If the students know that 7 x 3 = 21, then the students will automatically know that 3 x 7 = 21 because of the commutative property.  I feel that the students will be more efficient in their multiplication computations by knowing the properties.

 

I start the class by asking, "How many of you know what "properties" means?"  I give the students a few minutes to think about the question.  "Now, share your thoughts with a neighbor."  I call on a student to share with the whole class before continuing, "Properties are rules.  Today, we will use properties to help us find answers to multiplication problems."

I show the class the following video to explain the properties of multiplication:

http://studyjams.scholastic.com/studyjams/jams/math/multiplication-division/multiplication.htm

I let the students watch the video completely before asking them questions.  After showing the video, I review the multiplication properties with the students. 

Questions I ask:

1.  What happens when you multiply a number by zero?

2.  Can you change the order of the factors when you multiply?  Explain why or why not.

3.  When you multiply a number by 1, what will be your product?  Is this true for all numbers multiplied by 1?

After reviewing the multiplication properties, I give the students a quick vocabulary quiz. I call out number sentences and have the students hold up the index card with the vocabulary word that applies.

1.  7 x 1 = 7

2.  3 x 0 = 0

3. 100 x 1= 100

4.  4 x 2 = 8 and 2 x 4 = 8

5.  1,000 x x= 0

 

Partner Collaboration

15 minutes

In order for the students to have hands-on practice, I pair each student with a partner.  Working in pairs allow for student interaction, but it is small enough for all students to have a voice.  I give each student a copy of the assignment.  The students will first read the problem to get a clear understanding of what is being asked of them (MP1).  The students will discuss each problem together before writing their answer to the problem.  Both students must agree upon the answer, and be able to justify their answers (MP6).  I monitor and ask questions of students to assure understanding.  While monitoring, I may notice students who are struggling.  I help lead the students to the right answer by asking assessing questions.  Some questions that I ask are: (MP2)

1.  How many groups are there?

2.  How many are in a group?

3.  Is the product the same as one of your factors? If so, what property is that called?

4.  What happens when you multiply by zero?

5.  Can you explain the Commutative Property?

After the students finish their assignment, I bring the class back together as a whole.  I let some of the pairs share the word problems that they created.  I allow the other students to figure out the multiplication property and the number sentence  for each word problem.

By bringing the class back together as a whole, it gives the me an additional opportunity to hear what the students know.  I allow students to question each other as they discuss answers to the problems.

 

Early Finishers:  The students can practice the skill at the following site:  http://www.math-play.com/math-basketball-properties-of-multiplication/math-basketball-properties-of-multiplication.html

My Observations:

As the students worked, I walked around to monitor.  I was pleased with the discussion going on in the groups.  I noticed that some of the groups used models to help them with any difficult answer.  For example, in question 2, "Susan has 3 packages of pens.  There are 5 pens in a package.  Terri has 5 packages of pens.  There are 3 pens in each package" some students drew models.  I saw the students label Susan and draw 3 circles to represent the packages.  The students drew 5 pens in each circle.  For Terri, the students drew 5 circles to represent the packages and put 3 pens in each package.  From counting their pens, the students knew that each person had 15 pens.  Therefore, the commutative property would give them this answer.

 

Independent Activity/Exit Ticket

10 minutes

At the end of the lesson I have the students write the following assignment on a piece of paper.  I collect these to assess their mastery of the skill. 

 Students who do not master the skill will receive remediation.

 

 

Write your own multiplication number sentence for each property of multiplication.

Commutative Property:  _______________________

Identity Property:  _______________________

Zero Property:  _________________________

 

How does knowing the properties of multiplication  help you with multiplying? (MP7)

 

 

 

Homework

10 minutes

To give students more practice on the skill, give each student a homework sheet.  This will allow the parents to assist their child at home with the skill learned that day.