Hyphens are always used in compound numbers like twenty-one.
No.
No, a hyphen is not required.
No, a hyphen is not needed.
The correct spelling of hyphen is nephyh
It should be hyphenated if it's being used as an adjective.
No.
Tumblr URLs can't start or end with a hyphen.
No, faux pas doesn't require a hyphen.
yes you would spell it like this Ell[a] I think
No.
Yes
Yes