This document discusses factors, prime numbers, and composite numbers. It provides examples and explanations of these concepts, including: 1. The factors of 16 are 1, 2, 4, 8, and 16. 2. A prime number is a number greater than 1 that has exactly two factors, 1 and itself. 23 is a prime number. 3. A composite number can be written as a product of prime factors. 24 is a composite number with factors 1, 2, 3, 4, 6, 8, 12, and 24. Its prime factors are 2 and 3.

1. *rlumbers multiplied to form a product are factors of the product,
2X8:
,{t 16
factor iactor product
2 and I are factors of 16.
Wliat ather factors of 16 can you name?
Yauwill need ColourTiles or
congruent squares and grid paper.
b Find all the different rectangles you
carr make using each number
cf tiles from 2 to 20.
Record each rectangle on grid paper.
Write a multiplication sentence that
., describes the number of tiles in
each rectangle.
t' F*r which nurnbers of tiles could
,', you rn*ke only 1 rectangle? A2bglrectongle
'.
- ' Fsr which numbers of tiles could is ihe sarne os
yr:u rnake more than 1 rectangle? ali:g2nectongle.
ow Share
ycur work with another group of students.
are the fastors of 2? Of 3?
arg th* factors of 16? Of Z0?
ieould you find the factors of a number without
making rectangles?
I Explore fqctors qnd prime ond composite numbers, llE

2. )" Suppose You have 23 ColourTiles'
23 tiles"
You can make only 1 rectangle with all
23 has 2 factsrs: 1 and 23' -
i
A.prim,mtmbe! :!s.1d nbmb*r
A number with exactlY 2 factors, or€ater than 1 that is
1 and itsell is a Prime number' liui*iut* only uY 1 and itself'
23 is a Prime number'
P Suppos€ You have 24 ColourTiles'
24 tiles'
You can make 4 different rectangles with
1 x 24:24
2X 12:24 A comPosite number
can be written as a
p1*el*t **Xe.{a
r $.+,!rX,'f,X .X:*.
ffi3X8:24ffi4X6:24
n],2,3,4,6,8, 12, and 24'
24hasSfactors:
The prime factors of 24 are 2 and 3'
number'
A number with more than 2 factors is a composite
model your solutions'
You may use Colour Tiles or counters to
factsfs are prime factors?
r, List all the factCIrs of each number. which
al 75 30
bl 12 dl 50
fl 100 "l 20
gl hl 53
el 28
2. Write 3 numbers between 30 and 50 that have:
a! exactly 2 factors each b) more than 2 factors each
3. Write 3 nunrbers less than 100 that have exactly 4 factors each'
How do you know?
4. Tell if each number is prime or composite-
product of prime factors'
Write each composite nurnber as a I
93 cl 97 dl 87 el 73
"l 59
bl
tjnii ? Lesc
*6

3. 5. B€tween 20 and 28 students signed up for the chess club.
The students could not be divided exa{tly
into groups of 2, 3,4, or 5.
l{ow many students signed up for the chess club?
Show your work.
*" Three numbers between 70 and 80 are prime nurnbers.
What nurnbers are they?
Explain how you know they are prime numbers.
Flow many days in September
l-lave a prime number date?
How many have a composite
number date?
Show how you know.
E" l'{ow can you tellthat 32 and 95 are not
prime numbers without finding their factorsl
g. Carrnine and Nasra play a game with this spinner.
{armine gets a point if the pointer lands on a prime number.
lriasra gets a point if the pointer lands on a cornposite number.
|s this a fair game? How do you know?
to. Alexis said, "All prime numbers except for
the nunrber 2 are odd. So,allodd numbers
mu$t be prime numbers."
Do you agree with Alexis? Explain.
fi. Copy this table.
Prime Composite
Elren
odd
: '
,,
. ,r '
Sort th* nurnbers from Z to 30 ln the table. **Es$b€r$tr*t*gibr 1 ,,
:
Round eae h numb,er to tha nearest
hundred thousand, and to the
nearest million.
. 46 201 S8t!
e thinks thar 1 is neither prime . I 998 7S5
pcisite:
' 10S4{} $?S , i
'
why yor-r agree or disagree with hirn.
F*e*s { euestion S Unit2 Lesson 5 47