One-fourth an inch?

MustAskAre both correct, right?

No; only the second.

But then I hear " one-fourth a cup" is that incorrect too? I heard "one-fourth a cup" from at least three native speakers.

MustAsk then I hear " one-fourth a cup"

I don't. I think your native speakers are either drastically reducing 'of'—or saying 'one-fourth cup', which is also natural.

I say "a quarter inch."

eg, The recipe calls for a quarter cup of butter and a half cup of flour.

Time to bring the old issue up. What kind of advice can get on the use of these:

1. Half a million
2. A half million
3. A half of a million

MustAskTime to bring the old issue up. What kind of advice can get on the use of these:

Time to bring up the old advice.

Thanks! I'm guessing that all three examples are correct ?

MustAskOne-fourth of an inch

In my experience, it's usually like this:

[a third / a fourth / a fifth / ...] of [an inch / a cup / a tablespoon / ...]
[a half / a quarter / an eighth / a sixteenth] [inch / cup / tablespoon / ...]

(AmE)

CJ

MustAsk3. A half of a million

That one definitely sounds off to me.

What about:

A quarter of a million?
Three quarters million?
Three quarters hour?