# What are the prime factors of 45?

$45 = 3 \times 3 \times 5$

#### Explanation:

When doing prime factors, I like to start with a quick math fact I know (if I know one) and start there:

$45 = 9 \times 5$

5 is prime but 9 is not:

$45 = 3 \times 3 \times 5$

3 and 5 are both prime and so we're done

Mar 7, 2018

5,3.

#### Explanation:

Prime numbers from 0 - 10 are: 2,3,5,7.
Lets divide 45 in the short division method using prime numbers only.

$\frac{45}{5} \to \frac{9}{3} \to \frac{3}{3} \to 1$

therefore factors of 45 are:

$5 \cdot 3 \cdot 3$