a couple cups of coffee?

[Sweetpumpkin]

Hi,

I had a couple of cups of coffee, so now I'm wide awake.

Can I omit "of" in bold in the sentence above?
I googled and there are some usage without of: a couple cups of coffee.

Which one is right?

Thanks in advance,
sweetpumpkin

[Our Tort System]

I've heard that Americans oftentimes omit "of" in casual language.
But if you wish to be formal with somebody, refrain from omitting it!
_________________
If it's not easy, don't do it!
That's how I got where I am.

[Dozy]

Yes, to me the omission of "of" sounds like casual AmE.

In BrE the word "of" is not omitted, but in fast speech it can be much shortened and degraded so it may be easy to miss.