Composite Numbers

A composite number is a number with more than two divisors. In other words, it can be divided by itself, the number one and other numbers.

12, 72, 144.

Composite numbers can be expressed as products of powers of prime numbers. Such an expression is called a decomposition of a number in prime factors.

70 = 2 · 5 · 7


To factor a number or to decompose it into factors, carry successive divisions out between its prime divisors.

To make the divisions, use a vertical bar, to the right write the prime divisors and to the left the quotients.


Decomposing it into Factors

432 = 2 4 · 33