------ Note: The Information above this point will not be sent to your printer --------
Reteach: Factors
(Prime & Composite).
Remember that you can use what you know about factors to tell whether a number is a prime number, or a composite number.
Prime numbers have only 1 and themselves as factors.
Composite numbers have at least four factors, including 1 and themselves.
When you have written out all the multiplication sentences for a number, if you can draw a "smile", the number is a composite number. If you can only draw a straight line, the number is a prime number. |
17 is a prime number.
It doesn't "smile".
Its only factors are:
1 and 17.
|
10 is a composite number.
It “smiles”.
Its factors are:
1, 2, 5, and 10
|
|
Guided Practice
| 1. Decide if 13 is a prime number or a composite number. |
Write the multiplication sentence(s) for 13:
Does 13 "smile"? no
Is 13 a prime number or a composite number? prime |
1 x 13 = 13
|
| 2. Decide if 14 is a prime number or a composite number. |
Write the multiplication sentence(s) for 13:
Does 14 "smile"? yes
Is 14 a prime number or a composite number? composite |
1 x 14 = 14
2 x 7 = 14
|
|
--------- Page Break-------------
Independent Practice: Factors (Prime & Composite)
Use what you have learned about factors to determine whether each number is a prime number, or a composite number. |
a. 22 |
1 x 22 = 22
2 x 11 = 22
|
Prime or composite?
Composite
|
b. 19 |
1 x 19 = 19
|
Prime or composite?
Prime
|
c. 11 |
1 x 11 = 11
|
Prime or composite?
Prime
|
d. 25 |
1 x 25 = 25
5 x 5 = 25
|
Prime or composite?
Composite
|
--------- Page Break-------------
Independent Practice: Factors (Prime & Composite)
Use what you have learned about factors to determine whether each number is a prime number, or a composite number. |
e. 28 |
1 x 28 = 28
2 x 14 = 28
4 x 7 = 28
|
Prime or composite?
Composite
|
f. 40 |
1 x 40 = 40
2 x 20 = 40
4 x 10 = 40
5 x 8 = 40 |
Prime or composite?
Composite
|
g. 23 |
1 x 23 = 23
|
Prime or composite?
Prime
|
h. 8 |
1 x 8 = 8
2 x 4 = 8
|
Prime or composite?
Composite
|
------ Note: The Information below this point will not be sent to your printer --------
Related Resources
The various resources listed below are aligned to the same standard, (4OA04) taken from the CCSM (Common Core Standards For Mathematics) as the Factors and multiplesWorksheet shown above.
Find all factor pairs for a whole number in the range 1 to 100. Recognize that a ...
Charts
Games
Target Game
Number lines
Skip Counting - By 2, 3, 4, 5, & 6 (small marks at 1s, large marks at intervals and no numbers)- Skip Counting - By 7, 8, 9, 11, & 12 (small marks at 1s, large marks at intervals and no numbers)
- Skip Counting - By 11 (small marks at 1s, large marks every 11 and no numbers)
- Skip Counting - By 12 (small marks at 1s, large marks every 12 and no numbers)
Page
Worksheets
