99,999^2 – 1^2 = GMAT difference of squares quant question

99,999^2 – 1^2 = GMAT difference of squares quant question

Here’s the actual text of the question in a proper layout:

First things first, we need to figure out what sort of question this is. 

At first, it looks like something where we need to get it back into powers of 10, particularly given the answers. The problem is that there’s not really any good way to do so.

The next thing to notice is that it is one square minus another. That means that we also have access to a Difference of Squares:

So if we apply this rule to these numbers, we find:

Simplified, that gives us: 

We can further adjust this to be: 

The answer is E.