Prime factorization of $$$20$$$
Your Input
Find the prime factorization of $$$20$$$.
Solution
Start with the number $$$2$$$.
Determine whether $$$20$$$ is divisible by $$$2$$$.
It is divisible, thus, divide $$$20$$$ by $$${\color{green}2}$$$: $$$\frac{20}{2} = {\color{red}10}$$$.
Determine whether $$$10$$$ is divisible by $$$2$$$.
It is divisible, thus, divide $$$10$$$ by $$${\color{green}2}$$$: $$$\frac{10}{2} = {\color{red}5}$$$.
The prime number $$${\color{green}5}$$$ has no other factors then $$$1$$$ and $$${\color{green}5}$$$: $$$\frac{5}{5} = {\color{red}1}$$$.
Since we have obtained $$$1$$$, we are done.
Now, just count the number of occurences of the divisors (green numbers), and write down the prime factorization: $$$20 = 2^{2} \cdot 5$$$.
Answer
The prime factorization is $$$20 = 2^{2} \cdot 5$$$A.