MAFS3OA25 Commutative Property of Multiplication In Ms Adamss classroom library she has 5 rows of bookshelves with 3 books on each shelf as shown below Commutative Property of Multiplication ID: 243555
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Commutative Property of Multiplication
MAFS.3.OA.2.5Slide2
Commutative Property of Multiplication
In Ms. Adams’s classroom library, she has 5 rows of bookshelves with 3 books on each shelf, as shown below.Slide3
Commutative Property of Multiplication
In Ms. Prescott’s classroom library, she has 3 rows of bookshelves with 5 books on each shelf, as shown below.Slide4
Commutative Property of Multiplication
Who has more books?
Ms. Adams
Ms. PrescottSlide5
Commutative Property of Multiplication
Write a multiplication sentence that models each picture.
Ms. Adams
Ms. Prescott
5 × 3 = 15
3 × 5 = 15Slide6
Commutative Property of Multiplication
So who has more books?
They have the same number of books.
Ms. Adams
Ms. Prescott
5 × 3 = 15
3 × 5 = 15Slide7
Commutative Property of Multiplication
That means that
has the same value as…
5 × 3 = 15
3 × 5 = 15
This is because of the Commutative Property of Multiplication which states that
when you change the order of the factors, the product stays the same.Slide8
Let’s model the Commutative Property of Multiplication.
With counters or square tiles, model 3 rows of 5.
3 x 5 = 15
Now, model 5 rows of 3.
Doesn’t it look like the same array, just turned on its side?
It is.
5 x 3 = 15Slide9
Model 3 groups of 4.
Let’s model the Commutative Property of Multiplication.
3 x 4 = 12
Model 4 groups of 3.
4 x 3 = 12
Do the models look the same?
NO
But, is the product the same?
YES!Slide10
Write 2 multiplication equations for the following array.
3 × 5 = 15
5 × 3 = 15Slide11
Write 2 multiplication equations for the following array.
5 × 4 = 20
4 × 5 = 20Slide12
Write 2 multiplication equations for the following array.
2 × 4 = 8
4 × 2 = 8Slide13
Write 2 multiplication equations for the following array.
3 × 6 = 18
6 × 3 = 18Slide14
Why is the Commutative Property important?
If you know your “easy” facts, like your 1s, 2s, 5s, and 10s…
Then you also
know
many of your other facts too…all because of the Commutative Property of Multiplication.Slide15
Exit Ticket
Write the two multiplication equations shown by the arrays below.
What number would make this equation true?
5 × 4 = × 5