Bell Work
Mad Minutes
Arrays, Factors and
Prime vs. Composite
I can identify the factors of a number,
build arrays of the number and
determine whether it is prime or
composite.
Fluency Practice
Do the following Mental Math problems
(turn off the Smart Board).
Start with the number of days in one week.
Double that number.
Add the digits together.
Add 4.
Show me your answer on your fingers.
Start with the number 12.
Round that number to the nearest ten.
Double that number.
Multiply that by 10².
Whisper your answer to your neighbor.
Problem of the Day
Frank and Joe began reading an
adventure novel on the same day. If Frank
reads 8 pages each day and Joe reads 5
pages each day, what page will Joe be
reading when Frank is on page 56?
Vocabulary
• Array
• Number
Model
An arrangement of objects into
rows and columns that form a
rectangle.
. . .
. . .
. .
3 x 5 =. 15
product
factors
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Factors
• To test whether a counting
number is a factor of another
counting number, divide. If the
result is a counting number and
the remainder is 0, then it is a
factor.
4 is a factor of 12
because 12 ÷ 4 = 3 r. 0
6 is not a factor of 14
because 14 ÷ 6 = 2 r. 2
• One way to find all the factors of
a counting number is to find all
the factor pairs for that number.
Find all the factors of the
number 36
Number Models
1 x 36 = 36
3 x 12 = 36
2 x 18 = 36
4 x 9 = 36
6 x 6 = 36
The factors of 36 are
1, 2, 3, 4, 6, 9, 12, 18, 36
Arrays
• This is an array of 8 dots.
• It has 4 rows with 2 dots
in each row.
• It has 2 columns with 4
dots in each column.
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Number Model:
4x2=8
. .
. .
. .
What are all the factors of 8? How do you know?
Try it!
• Make an array on your slate for the number 12.
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2 x 6 = 12
Come up and draw another array for the number 12
and write it’s number model.
Make a list of the factors of 12.
Check it Out!
Watch One Hundred Hungry Ants video
http://www.youtube.com/watch?v=kmdSUHPwJtc
What Do You Notice?
Draw all possible arrays and list factor pairs for these numbers:
2, 4, 5, 10, and 11.
2
4
5
10
Arrays:
Factor Pairs:
What do you notice about the data you gathered for each number?
11
Prime Numbers
Watch the BrainPOP video and take the online quiz.
• http://www.brainpop.com/math/numbersandoperations/primenumbers
/
Independent Practice
You have 10 minutes to complete the following:
Do Journal p. 16 with a partner.
http://www.vickiblackwell.com/timer.html?vm=r
Factor Captor
Get a partner, a game board from the
back counter and a piece of paper to keep
score.
SRB Page 306
Smartboard Game
http://www.sheppardsoftware.com/mathgames/numbers/fruit_shoot_prime.htm
Closure
I can identify the factors of a number, build
arrays of the number and determine
whether it is prime or composite.
Go over the Journal pages.
Class discussion:
What does an array tell us about a number?
Why do we need to know the factors of a number?
What is the difference between prime and
composite numbers?
What strategies did you use to win Factor Captor?
Exit Slip
You have 3 minutes to complete your exit slip.
When you finish, turn it into your class’s box and start on
tonight’s homework.
Number
3
6
19
24
27
41
Factors
Prime or Composite
Homework
Study Link 1-6, p. 15