Math Message Lesson 1 . 1
Browse through your journal. Then
read “Welcome to Fifth Grade Everyday
Mathematics,” on page 1 in your journal.
Unit 1 - EDM
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
Familiarize yourself with your Student
Reference Book
Unit 1 - EDM
Math Message Lesson 1 . 2
Read page 10 in your SRB. Then
draw a rectangular array made up of 12
dots. You may use counters to help you.
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Rectangular Arrays
Each row has the same number of
parts
 Each column has the same number of
parts
 Each array has a rectangular shape.

Unit 1 - EDM
Take out six counters (rainbow cubes)
 Arrange the six counters in a
rectangular array



Number model - 2 * 3 = 6
2 rows by 3 columns = 6
Unit 1 - EDM
Commutative Property
The order in which two numbers are
multiplied makes no difference.
 For example, 2 * 3 = 6 and 3 * 2 = 6
 Also called the “turn around rule”

Unit 1 - EDM
Math Message Lesson 1 . 3
Take a sheet of dot paper. Use
counters (rainbow cubes) to make all
possible arrays of 15 objects. Record the
arrays on the dot paper. Write a number
model for each array.
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Factors
Factor
 Product
 Factor Pair

3 * 5 = 15
Factors
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Product
Find all of the factors for 18
1 * 18 = 18
 18 * 1 = 18
 2 * 9 = 18
 9 * 2 = 18
 3 * 6 = 18
 6 * 3 = 18

Factors of 18 are:
(1, 2, 3, 6, 9, 18)
Unit 1 - EDM
Math Message Lesson 1 . 4
Which of the following number are
factors of 36?
1, 2, 3, 4, 5, 6, 7, 8, 9, 10
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Finding Factors of a
Number
Multiplication and division are
related
 They are opposites
 If you know your multiplication
facts, you know your division
facts
 We can find factors of a number
by checking for divisibility

Unit 1 - EDM
Divisibility – a number is divisible by another
number if the result of division is a whole number.
Is 54 divisible by 9?
 Is 25 divisible by 6?
 Is 8 a factor of 48?
 Is 4 a factor of 30?

Unit 1 - EDM
Math Message Lesson 1 . 5
Solve problems 1 and 2 at the top of
journal page 12.
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Divisibility

A number is divisible by a whole
number is the remainder in the
division is zero and the quotient is a
whole number.
 We can use a calculator to test for
divisibility
 Example: 27 is not divisible by 5
because 5.4 is not a whole number.
Unit 1 - EDM
Divisibility Tests - 2
A number is divisible by 2 if it ends in 0,
2, 4, 6, or 8.
 We also call those numbers even
numbers.

44, 12, 28, 62, 108, 256, 80
Unit 1 - EDM
Divisibility Tests - 3
A number is divisible by 3 if the sum of
its digits is divisible by 3.
 Example:

237
410
2 + 3 + 7 = 12
4+1+0=5
1+2=3
Unit 1 - EDM
Divisibility Test - 6

A number is divisible by 6 if it is divisible
by both 2 and 3.
426
Is it even? Yes
4 + 2 + 6 = 12
1+2=3
Unit 1 - EDM
Divisibility Test - 9
A number is divisible by 9 if the sum of
its digits is divisible by 9.
 Example:

198
429
1 + 9 + 8 = 18
4 + 2 + 9 = 15
1+8=9
1+5=6
Unit 1 - EDM
Divisibility Tests – 5

A number is divisible by 5 if it ends in a
5 or a 0.

Example: 25, 30, 105, 1260
Unit 1 - EDM
Divisibility Tests – 10

A number is divisible by 10 if it ends in a
zero.

Example: 10, 20, 1450, 370
Unit 1 - EDM
Math Message Lesson 1 . 6
Draw all the arrays possible for these
numbers: 4, 10, 16.
Draw all the arrays possible for these
numbers: 2, 5, 11.
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Prime and Composite
Numbers
A prime number has exactly two
factors – 1 and the number
itself.
 A composite number has more
than two factors.
 The number one is neither
prime nor composite. (It has
only one factor.)

Unit 1 - EDM
Prime or Composite?
25
17
Unit 1 - EDM
Math Message Lesson 1 . 7
Use the rainbow cubes. Try to make a
rectangular array that has an equal number
of rows and columns for each of the
following numbers:
14 16 18
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Square Numbers
Has the same number of rows
and columns
 Has an odd number of factors
 Can be written using an
exponent
42
4 * 4 = 16

Unit 1 - EDM
Exponents and Base Numbers
exponent
2
4
base number
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Math Message Lesson 1 . 8
Find the numbers n and m that make
these statements true:
n*n=4
m2 = 81
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Unsquaring Numbers
Solving m2=81 is unsquaring a
number.
 What number multiplied by itself
is equal to 289?
 After unsquaring a number, the
result is called the square root.

Unit 1 - EDM
Unsquaring More Numbers
What number when multiplied by itself
equals 49?
 What number when multiplied by itself
equals 25?
 What number when multiplied by itself
equals 36?

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Unsquaring More Numbers
(calculator)
196
441
676
900
1024
1849
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Math Message Lesson 1 . 9
8 + 8 and 4 * 4 are two names for the
number 16. Write at least five other names
for 16.
Unit 1 - EDM
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Factor Strings and
Prime Factorization
Factor Strings
24 = 3 * 2 * 4
12 = 2 * 3 * 2
How can we make the longest
factor strings?
Unit 1 - EDM
180
10
18
180
10
18
180
18
10
2
5
6
3
180
18
10
2
5
6
2
3
3
Prime Factor String
180 = 2 * 5 * 2 * 3 * 3
Prime Factorization using Exponential Notation
180 = 22 * 32 * 5
Unit 1 - EDM
Math Message Lesson 1 . 10
Please complete the Time to Reflect
questions on journal page 27. 
Unit 1 - EDM