These are used for separating words:
- she was 30 years-old
- he was a two-timer
- The address was twelve-forty-two S Ave.
- He was forty-two
And to spell out words:
- "Apple," she repeated at the spelling bee. "A-P-P-L-E. Apple."
"The en dash connects things that are related to each other by distance, as in the May–September issue of a magazine.... En dashes specify any kind of range, which is why they properly appear in indexes when a range of pages is cited (e.g., 147–48). En dashes are also used to connect a prefix to a proper open compound: for example, pre–World War II. In that example, 'pre' is connected to the open compound 'World War II'" (from The Chicago Manual of Style Online).
Visit: http://www.chicagomanualofstyle.org/dam/jcr:a99f4e58-525d-4006-9b64-4c4e8f24c3a8/cmos-linkgraphic.gif for more info.
A good way to remember the difference between the en dash versus the em dash is a little saying I use: The letter 'n' is just a shorter version of the letter 'm' and thus the en dash is a shorter version of the em dash.
I’ve always struggled with writing grammar and punctuation. Almost all the uses of the em-dash are second nature to me, however I’ve never been able to find an accurate use of the em-dash when interrupting a quote with an action. I’ve spent lots of timer researching this but it’s hard to find a straight answer on the internet. Many sites counteract each other, or they don’t have this specific information. But finally I found my answer in “Spirit Walk: Walk of the Spirits” by Richie Tankersley Cusick.
“Well”—Miranda drew a deep breath—“I wasn’t okay just a few minutes ago. But I think I am now” (pg 274).
So that's the difference between hyphens and the two different forms of dashes.
Hope this was useful!