Answer
$18 = 2 \cdot 3\cdot 3$
Work Step by Step
The $\textit{prime factorization}$ of a number is obtained by writing the number as a product of primes.
To determine the prime factorization of $18$ we write the number as a product of factors and continue the process until all factors are prime numbers.
We start by writing $18$ as a product of two numbers:
$18=2\cdot 9$.
The number $2$ is prime, but $9$ is not. So we write $9=3\cdot 3$:
$18=2\cdot 3\cdot 3$.
Now each factor is a prime number, therefore the prime factorization of $18$ is $2\cdot 3\cdot 3$.
