Primary Mathematics/Factors and Primes

From Wikibooks, open books for an open world
< Primary Mathematics
Jump to: navigation, search
Primary Mathematics
 ← Dividing numbers Factors and Primes Method for Factoring → 


Factors and Primes[edit]

Factors are numbers that you can multiply together to get another number. For example: 8 and 11 are factors of 88 as 8 x 11 = 88. Similarly, 10 is a factor of 100 as 10 x 10 is 100.

Prime factors are factors which are prime numbers

55  = 5 x 11
100 = 2 x 5 x 2 x 5

Because 2, 5, and 11 cannot be divided by any number but 1 and itself, these numbers are called prime. Prime numbers are an important part of mathematics, and the problem of factoring large numbers into primes remains fundamental to the study of computer science. Factoring a number like 64 often requires more than one step:

64  = 2 x 32 (32 is not prime)
 or = 2 x 2 x 16 (16 is not prime)
 or = 2 x 2 x 2 x 8 (8 is not prime)
 or = 2 x 2 x 2 x 2 x 4 (4 is not prime)
 or = 2 x 2 x 2 x 2 x 2 x 2


Primary Mathematics
 ← Dividing numbers Factors and Primes Method for Factoring →