Don't hyphenate; ongoing is one word.
You can.
You do not hyphenate one by one. See, for example, the use of those words in the definition of "count" in the Random House Webster's Unabridged Dictionary.
The quarter is a unit of mass and the meter is a unit of length !
4 units is the answer because one quarter has 4
You do not generally hyphenate the word stepchild, because it is not a hyphenated word. If the question is where to hyphenate stepchild if you have to break it across two lines, it is not difficult to determine this, because the two syllables are actually separate words: step and child. If you have to hyphenate the word to break it, you would put step- on one line and child on the next. If the word is all on one line, you do not hyphenate it.
Hyphenate! One-eyed is how to tackle this one!
You do not. It is a single word, not a hyphenated one.
A quarter (quarter gallon) is a unit of volume, not a unit of mass like the gram.
You do not need to hyphenate.
You do not hyphenate the number.
You hyphenate it only at the hyphen.