Prime or Composite
Factor Trees/Prime Factorization
Divisibility
Explain It
Division Facts
100
Is 13 prime or composite? How do you know?
13 is prime because it's only factors are 1 and itself. OR
13 is a prime number because it is only divisible by 1 and itself.
100
What is the prime factorization of 12?
Create a factor tree for 12.
OR
100
All numbers are divisible by 1. True or false?
True.
100
What is a prime number?
A number that only has factors of 1 and itself.
or
A number that is only divisible by 1 or itself.
100
If 6x8 = 48 then 48÷8 =
6.
200
List the factors of each number. State if it's prime or composite.
23
18
23 (prime) 1, 23
18 (composite) 1, 2, 3, 6, 9, 18
200
What is the prime factorization of 21?
Use a factor tree.
PF: 7 x 3
200
What is the divisibility rule for 5?
A number is divisible by 5 if it's one's digit is a 0 or 5.
200
Sara says 2 is a composite number. Is she correct? Explain why or why not.
She is incorrect. 2 is the only even prime number. 2's only factors are 1 and itself.
200
Write all the facts for this fact triangle on your whiteboard.
8 x 4 = 32
4 x 8 = 32
32 ÷ 8 = 4
32 ÷ 4 = 8
300
Sort into prime or composite or neither:
0, 39, 27, 60, 48, 29
Prime: 29
Neither: 0
Composite: 39, 27, 60, 48
300
What is the prime factorization of 81?
Draw a factor tree to show your work?
PF: 3X3X3X3
300
Which numbers are divisible by 2?
222, 20 8448, 33, 2937, 81
222, 20, 8448
300
A rectangles has 16 squares. What could the dimensions be? List all possibilities.
1 x 16, 16 x 1
2 x 8, 8 x 2
4 x 4
300
Write all the facts on your whiteboard for this triangle (4):
7 x 9 = 63
9 x 7 = 63
63 ÷ 9 = 7
63 ÷7 =9
400
Sort into prime and composite:
452, 29, 23, 7, 81
Prime: 7, 29, 23
Composite: 452, 81
400
What is the prime factorization of 20?
Show both ways (two different ways)
PF= 2 X 2 X 5
400
What numbers are divisible by 4?
12, 80, 14, 48, 50, 9
12, 80, 48
400
Explain your reasoning.
They are both correct because 2, 6, 7, 21 are all factors of 42. Each student also did their factor tree to only have prime numbers at the bottom.
400
Solve all:
a) If 5 x 4 = 20 then 20 ÷ 4 =
b) If 9 x 9 = 81 then 81 ÷ 9 =
c) If 8 x 7 = 56 then 56 ÷ 7 =
a) If 5 x 4 = 20 then 20 ÷ 4 = 5
b) If 9 x 9 = 81 then 81 ÷ 9 = 9
c) If 8 x 7 = 56 then 56 ÷ 7 = 8
500
What numbers are neither prime or composite?
0 or 1.
500
Draw ALL both possible factor trees for 36.
(There are 4)
500
Sort using a venn diagram which ones are divisible by 2 and 5 or both
50, 36, 35, 44, 28
2- 36, 38, 44
Both- 50
5- 35
500
Mrs Harvey wants to set up chairs in the gym for an assembly. There are 50 chairs. How could the chairs be set up. Draw a picture or use grid paper to show all the possibilities. Write a sentence to answer the question.
Possible dimensions and rows:
1 x 50, 50 x 1
2 x 25, 25 x 2
10 x 5, 5 x 10
Therefore Mrs Harvey could have 1 row of 50, 2 rows of 25 or 10 rows of 5.
500
Solve all 3
a) 400 ÷ 10
b) 1200 ÷ 12
c) 350 ÷7
a) 40
b) 100
c) 50