Question

How do you write the prime factorization of 28?

Answer 1

The prime factorization of 28 is `2^2 * 7`.

Explanation:

First, you can find any factor pair of 28. For example, the first one I think of is 74 (but 142 works as well). 7 is already prime, so that is already part of the prime factorization.
Now, 4 isn't prime, so we must split that into a factor pair of some sort. In this case, we see automatically that `4 = 2^2`, and the 2's are prime. So the prime factoring ends there.

Putting everything together, we get `28 = 2^2 * 7`.

Answer 2

`2xx2xx7" " ->" "2^2xx7`

Explanation:

If you ever have any doubts you can always do a quick rough sketch of a factor tree. Mine is too neat for exam conditions.

Starting point: 28 is even so 2 will divide into it exactly.

It is helpful if you can commit some of the prime numbers to memory. A quick search on the internet will provide a list for you. I suggest you use 'images'