1. Hyphens and Dashes

2. Hyphen Rules
Hyphens are used to connect two or more words (and numbers) into a single concept.
Italian-American communities are vibrant and interesting.
Tina’s money-saving measures have helped her save 1,000 dollars.
Mom stopped buying two-liter bottles and started buying half-liter bottles, instead.
We also use hyphens in the numbers (which are adjectives) 21 through 99.
Before the big test, Thomas studied for twenty-two hours over seven days.
I want ninety-nine red balloons.

3. Hyphens…
Hyphens are mostly used to combine compound adjectives. Compound adjectives modify a word TOGETHER. They aren’t each modifying the word separately. If you can’t use the word “and” between the words, and you can’t pause for a few beats between the words, you’re seeing compound adjectives.
It was an ill-fated plan.
She didn’t want a run-of-the-mill pony; she wanted an appaloosa.
Hyphens can also connect parts of compound nouns.
Will you be a go-between for Sandy and me? We aren’t speaking.
This documentary about whales in captivity is a real eye-opener!

4. Hyphens… Dictionary rule:
To check whether a compound noun is two words, one word, or hyphenated, you sometimes need to look it up in the dictionary.
If you can't find the word in the dictionary, treat the noun as separate words.
For example, these “eye” words are all supposed to be treated differently; the only way to know what to do is to look them up: eyewitness, eye shadow, eye- opener.

5. Hyphens… A Trick: Examples:
If you are confused about a phrase that has a few different forms, you can figure out what to do based on what part of speech the phrase is performing! 
If it’s a verb, write it as separate words
If it’s a noun, write it as one word
If it’s an adjective, write it as one word
Examples:
The engine will eventually break down. (verb)
We suffered a breakdown in communications. (noun)
Please clean up your room. (verb)
That Superfund site will require specialized cleanup procedures. (adjective)

6. Dash Rules
Dashes usually separate extra information from the rest of the sentence. Parentheses also do this, but they de-emphasize. Dashes emphasize whatever they surround.
Mr. Lee is suited to the job—he has more experience than everyone else in the department—but he has been dealing with some things at home recently and would probably not be available for hire. 
Dashes are also used to indicate an interruption. This usually is useful when transcribing speech.
They student began to say, “An organic solvent will only work with—” when someone’s cell phone rang and cut her off.

7. Dashes…
Next, dashes should be used to set off parenthetical elements when the parenthetical element is a list with commas (this helps avoid confusion).
Ex: All four of them—Bob, Jeffrey, Jason, and Brett—did well in college.
Dashes are sometimes used as a substitute for a colon, but this use doesn’t belong in formal writing.
Ex: There was only one person suited to the job—Mr. Lee.

8. En-dash Rules
The en-dash, which is shorter than an em-dash (the standard dash) and longer than a hyphen, is used to indicate a range of values, such as a span of time or numerical quantities (it is similar to using the words “to” and “from”). 
Examples
9 AM – 5 PM
Monday – Friday
ages 5 – 8
Notice that this mark is a little longer than a hyphen and a little shorter than a dash.

9. HOW TO TYPE HYPHENS AND DASHES
A hyphen is created by typing the hyphen key (next to the zero) ONE time. Do not space around the hyphen. It should touch both words it connects.
DASHES:
You make a dash by typing the hyphen key (by the zero) twice. It will ONLY work if you do not type a space after the last word or before the next word. If you put in any spaces, it will just look like this -- (two hyphens) or it will convert into an en-dash (which is too short).
 EN-DASHES:
The computer will make en-dashes for you because it can recognize a range of numbers or times.