Prime vs Composite
Brenda said that the number 2 is prime becuase it has only two factors. Carla said that the number 2 is composite because it is even, and all even numbers are composite. Who is correct?
Brenda is correct
Create a number tree for 42 to show its prime factors.
ex: 42 -> 2 x 21
21 -> 3 x 7
Prime factors: 2, 3, 7
List all the factors of 36.
Hint: Use a number rainbow...
1, 2, 3, 4, 6, 9, 12, 18, 36
In the power 43, which number represents the base, and which number represents the exponent?
4 is the base, and 3 is the exponent.
What is the only even prime number? Why?
2, because any other even number is divisible by 2.
Is 61 prime or composite?
If it is composite, name two factors.
Prime
Create a number tree for 72 to show its prime factors.
ex: 72 -> 2 x 36
36 - > 3 x 12
12 -> 2 x 6
6-> 2 x 3
Prime factors: 2, 2, 2, 3, 3
What are the first 5 multiples of 12?
12, 24, 36, 48, 60
Write 3 x 3 x 3 x 4 x 4 using exponents.
33 x 42
True or false: There is an infinite amount of prime numbers.
True!
Name all the prime numbers below 10.
2, 3, 5, & 7
Create a number tree for 144 to show its prime factors.
ex: 144 -> 2 x 72
72 -> 2 x 36
36 -> 3 x 12
12 -> 2 x 6
6 -> 2 x 3
Prime factors: 2, 2, 2, 2, 3, 3
Which number has more factors: 54 or 90. Prove it.
Hint: Use number rainbows...
90 has more factors than 54.54.54.
Write 43 x 22 x 5 as multiplication (without exponents).
4 x 4 x 4 x 2 x 2 x 5
What is the smallest prime number after 100?
101
It's the first prime number after 100
Four students each wrote down a number:
Mike- 35
Boo- 39
Sully- 37
Roz-33
Which student wrote down a prime number?
Sully
Will the prime factors of a number tree ever change if you start with different factors? Why or why not?
No, the prime factors of a number tree will always be the same, even if you build it differently.
This is because every composite number has only one unique prime factorization.
You may start with different factor pairs, but the result will always break down to the same set of prime numbers.
List all factors of 40.
1, 2, 4, 5, 8, 10, 20, 40
Write the prime factorization of 256 using exponents.
256 = 28
When building a number tree, do you need to break down a prime number into its factors of 1 and itself? Why or why not?
No, you do not need to break down a prime number into its factors of 1 and itself.
This is because a prime number is already in its simplest form—it only has two factors: 1 and itself.
The purpose of a Number Tree is to break composite numbers into their prime factors, so once you reach a prime number, you stop.
I am a number divisible by 2 and 3. Am I prime or composite?
Composite! I have at least 3 factors already (2, 3, and 1)
Create a number tree for 360 to show its prime factors.
Ex: 360 -> 10 x 36
10 -> 2 x 5 | 36 -> 3 x 12
12 -> 3 x 4
4 -> 2 x 2
Prime factors: 2, 2, 2, 3, 3, 5
I am a number between 30 and 60. I am a multiple of both 6 and 9. What number am I?
54
I am the lowest common multiple (LCM) of 6 and 9!
Isabella wrote the number 36 as 22×32
Why did she write it this way, and what does it show about the number 36?
She wrote it this way to show the prime factorization of 36.
It means 36 is made by multiplying two 2s and two 3s:
2×2×3×3
The Eagles football team uses only composite numbers on their jerseys. Each of the following numbers could have been on a jersey EXCEPT-
27
81
43
46
43- is prime