Download Lesson 1 - St. Anastasia Catholic School

Lesson 1: I can multiply multi-digit whole
numbers and multiples of 10 using
place value patterns and the
distributive and associative properties.
Associative Property
5th Grade Module 2 – Lesson 1
Distributive Property
We are going to learn how to multiply multi-digit whole
numbers using the “Associative Property”
The Associative Property of Multiplication can help you
to multiply quickly and correctly.
It means that we can re-group our factors but still get
the same product.
(2 x 5) x 3 = 2 x (5 x 3)
10 x 3 = 2 x 15
30 = 30
It is important to remember to multiply what
is in the parentheses ( ) first!
5th Grade Module 2 – Lesson 1
Concept Development
Get Your Place Value Charts Ready!
Let’s Multiply 4 x 30 using units
To find the product of 4 x 30, we can start by multiplying
using whole numbers. Renaming 30 as 3 tens.
Remember we need to state the unit in our product.
12 tens
4 x 3 tens = __________________
Show 12 tens on your place value chart.
What is 12 tens in standard form?
12 tens = 120
So…
4 x 30 = 120
5th Grade Module 2 – Lesson 1
Let’s solve
4 tens x 3 tens
How can the previous problem help us solve this problem?
Let’s multiply the whole
numbers first then the units.
We can also record this problem like
this …
4 x 3 = 12
10 x 10
ten x ten = hundred
So,
4 tens x 3 tens = 12 hundreds
12 hundreds = 1,200
(4 x 3 ) x 100
12 x 100
= 1200
5th Grade Module 2 – Lesson 1
4 tens x 3 hundreds = ____
12,000
How is this problem different than
4 tens x 3 tens?
We are multiplying tens
and hundreds, not tens
& tens.
Let’s record and solve:
So,
44 tens
tensxx33hundreds
hundreds =
12as thousands
4 tens is the same
3 hundreds =
Or 3 x _____
100
4 x 10
We can express our
(4 x 10) x12,000
(3 x 100)
problem this way.
OR
(4 x 3) x (10 x 100)
12
x
1000
Is this equation equal
to the one above?
12,000
5th Grade Module 2 – Lesson 1
Let’s try this one…
120,000
4 thousands x 3 tens = ____
Let’s record and solve:
4 thousands x 3 tens
4 thousands is the same as
3 tens =
4
1,000
_______
x ________
3 x _____
10
____
(4 x 1000) x (3 x 10)
4,000 x 30
120,000
We can express our
problem this way.
OR
(4 x 3) x (1000 x 10)
12
x 10,000
Here is a different
way we can set up
our problem.
120,000
5th Grade Module 2 – Lesson 1
60 x 5
(6 x 10) x 5
Are both these
equations equal
to 60 x 5
Turn & Talk
(6 x 5) x 10
When we change
thesolve
order this
of the
factors we are
Let’s
using
using the commutative
(6 xproperty.
5) x 10
When we GROUP the factors differently we are
using the associative property of multiplication
30 x 10
300
5th Grade Module 2 – Lesson 1
60 x 50
Work with your partner to solve this problem and
explain how you solved it.
Possible Solution:
(6 x 5) x (10 x 10)
30 x 100
3,000
5th Grade Module 2 – Lesson 1
Find the product of 451 x 8
3,608
(use any method you want)
What would make the distributive property useful
here?
Why does it help here, but we didn’t really use it
in our other problems?
Distributive Property = (400 x 8) + (50 x 8) + (1 x 8)
3200 + 400 + 8
3,608
5th Grade Module 2 – Lesson 1
How can 451 x 8 help you solve these?
1). 451 x 80
36,080
2). 4,510 x 80
3). 4,510 x 800
360,080
Evaluate these problems with your partner.
5th Grade Module 2 – Lesson 1
3,608,000
Get Ready to Complete the
Problem Set on Your Own!
Complete Pages 2.A.9- 2.A.11
Try your Best!
5th Grade Module 1 – Lesson 13
5th Grade Module 1 – Lesson 13
EXIT
TICKET
5th Grade Module 1 – Lesson 5