• A factor is a number that divides another number without a remainder.
  

  Number	Factors
  1 2	1 ,2,3,4,6,1 2
  1 6	1 ,2,4,8,1 6
  39	1 ,3,1 3,39

A natural number with only two factors, one and itself is a prime number. Or any number that only can be divided by 1 and itself. Prime numbers have exactly 2 different factors

Prime Numbers up to 100.

Composite Numbers

• Any number that has more factors than just itself and 1 .They can be said to be natural number other than 1 which are not prime numbers.They can be expressed as a product of two or more prime factors.
  9 = 3 x 3
  12 = 2 x 2 x 3
  105 = 3 x 5 x 7
• The same number can be repeated several times in some situations.
  32 = 2 x 2 x 2 x 2 x 2 = 2⁵
  72 =2 x 2 x 2 x 3 x 3 = 2³x 3²
• To express a number in terms of prime factors ,it is best to take the numbers from the smallest and divide by each of them as many times as possible before going to the next.
  
  Example
  Express the following numbers in terms of their prime factors
  1. 300
  2. 196
  
  Solution
  
  
  1.  
     

     2	300
     2	150
     3	75
     5	25
     5	5
     	1

     
     300 = 2 x 2 x 3 x 5 x 5
     = 2²x 3 x 5²
  2.  
     

     2	196
     2	98
     7	49
     7	7
     	1

     196 = 2 x 2 x 7 x 7
     = 2² x 7²

Exceptions