Prime/Composite Number Lesson

Prime/Composite Number Lesson-Absent Students

Prime numbers have only 2 factors, 1 and itself.

Composite numbers have 3 or more factors.

• 1 is neither prime nor composite

• 2 is the only even prime number

​17 only has 2 factors, 1 and 17, so it is a prime number.

​4 has 3 factors: 1, 2, and 4. This makes it a composite number.

​The 3 numbers are 3, 7, and 24.

​3=1,3 Only 2 factors, so it's a prime number.

​7=1,7 Only 2 factors, so it's also a prime number.

​24=1,2,3,4,6,8,12,24 It has 8 factors, so it's a composite number.

​99- 1,3,9,11,33,99 There's 6 factors, so it's a composite number.

​30 is the composite number because it has the factors 1,2,3,5,6,10,15,30.

​2 is the prime number because it only has 2 factors, 1 and 2.

Multiple Choice

Which shows all the factors for 17?

• 1, 2, 15, 17

• 1, 7, 10, 17

• 1, 17

• 17

Multiple Choice

4 is a composite number because

• it has exactly 2 factors.

• it has 3 or more factors.

• it is an even number.

• it is an odd number.

Multiple Choice

Which list shows all the factors for the number?

• 14=1, 2, 6, 14

• 18= 1, 2, 9, 18

• 16= 1, 2, 4, 8, 16

• 10= 1, 10

Multiple Choice

99 is a prime number.

• True

• False

Multiple Choice

Which number is the only even prime number?

• 2

• 4

• 5

• 6

Multiple Choice

Besides 1 and 21, which is another factor of 21?

• 5

• 4

• 2

• 3

Multiple Choice

Which is the only even number that is prime?

• 29

• 13

• 2

• 12

Multiple Choice

Which statement is true about the number 27?

• It's prime because it has only 2 factors.

• It's prime because it is an odd number.

• It's composite because it is an even number.

• It's composite because it has 3 or more factors.

Multiple Choice

Which is not a composite number between 20 and 30?

• 26

• 34

• 25

• 24