Rules on Prime and Composite Numbers

is a number greater than 1 that has exactly two factors, itself and 1.

• Base

• Composite Number

• Prime Number

• Greatest Common Factor (GCF)

is a number greater than 1 that has more than two factors.

• Composite Number

• Greatest Common Factor (GCF)

• Compatible Number

• Divisibility Rules

a whole number greater than 1 that has exactly two factors (1 and itself)

• dividend

• prime number

• composite number

• factor

a whole number with two or more factors

• composite number

• divisor

• factor

• prime number

The number 21 is ​ (a)   because it has ​ (b)  

• composite

• prime

• more than 1 factor pair

• exactly 1 factor pair

1 is neither prime nor composite

• True

• False

Are each of these numbers prime or composite?

• prime

• 15

• composite

• 10

• prime

• 7

• composite

• 12

• composite

• 3

The number 17 is ​ (a)   because it has ​ (b)  

• prime

• composite

• exactly 1 factor pair

• more than 1 factor pair

The number 11 is​ (a)   because it has ​ (b)  

• prime

• composite

• exactly 2 factors

• more than 2 factors

The number 25 is ​ (a)   because it has ​ (b)  

• composite

• prime

• more than 2 factors

• exactly 2 factors