Factor

One of two or more whole numbers that are multiplied to get a product

Example: 9 and 7 are both factors of 63 because 9 X 7 = 63

Proper Factor

All the factors of a number, except the number itself

Example: The Proper factors of 16 are 1,2,4, & 8

Divisor

A number that divided a given number leaving a zero remainder

Example: 5 is a divisor of 20 since 20 ÷ 5 = 4

A divisor of a given number is also known as a factor of that number

Prime Number

A number with exactly 2 factors: 1 and itself

Example: 53 is a prime number because it cannot be broken down into smaller whole numbers

One is not a prime number because it has only 1 factor

Composite Number

A whole number with factors other than 1 and itself

Example: 20 is a composite number because it's factors are 1,2,4,5,10,20

Abundant

A number for which the sum of the proper factors is grater than the number itself

Example: The proper factors of 24 are: 1,2,3,4,6,8,12. Their sum is 36 making 24 abundant.

Deficient

A number for which the sum of all the proper factors is less than the number itself

Example: The proper factors of 27 are: 1,3,9. Their sum is 13 making 27 deficient.

Perfect

A number for which the sum of all its proper factors is the number itself

Example: The proper factors of 28 are: 1,2,4, 7,14. Their sum is 28 making 28 perfect.

Multiple

The product of a given whole number and another whole number

Example: 6 is a multiple of 2 and 3 because 2 X 3 = 6

Even Number

A number that is a multiple of 2. 

Even numbers end in 0,2,4,6,8.

Odd Number

A number that is not a multiple of 2.

Odd numbers end in 1,3,5,7,9.