According to the Chicago Manual of Style, both the noun and adjective forms of ages should be hyphenated (a three-year-old, ten-year-old Scotch). Other styles may not require it for nouns.
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You do not need to hyphenate.
You do not hyphenate the number.
You would hyphenate "thank you" when it is used as an adjective before a noun, such as in "a thank-you card."
Don't hyphenate; ongoing is one word.
You hyphenate it only at the hyphen.
I think it's more accepted to hyphenate it.
Can you, or should you? You can hyphenate it if you're moving between lines in a paragraph and need to break up the word. You shouldn't hyphenate it normally.
You can hyphenate the word improvement like this: im-prove-ment.
You mean at the end of a line? Well it depends on how much room you have hyphenate at a syllable is probably best. If you have little space before the end of the line don't hyphenate a word. You could hyphenate like this trans- portation.
No...
You can hyphenate 3 bedroom when it is used in a list. It is usually not hyphenated when it is used by itself.