How To Use a Colon

The punctuation mark, that is, not the part of human anatomy.  A post on that would be all kinds of gross. 

Specifically, here’s how I teach the use of the colon: I made up a formula that defines its function.

Did you see that?  I demonstrated it in that last sentence.  What exactly does the colon do?  It points to the rest of the sentence; it says, “And now, here’s the exciting conclusion to the situation set up in the first half of the sentence!”

The formula that I present to students is below.

: = →

Colon equals arrow.  Bonus: it looks like an emoticon.  That dude has warped nostrils, but at least he seems happy. 

Consider this: The answer is this four.  How would you punctuate that?  By putting a colon after the word “this,” of course.  The answer is this: four. 

How can you know that’s right?  Picture the colon’s equal in its place: The answer is this → four.  Makes perfect sense.