Please could you explain the meaning of ‘what’ in the following sentence?
‘It’s been, what, five years!’
(The man split up with his girlfriend five years ago and suddenly phoned to invite her for lunch. She rejected the invitation, saying this phrase.)
It means “I think it has been five years, do you agree?”
“What” is always used, even though the question can be about time. It is only used when asking about a number or quantity or amount of time.
"It costs, what, 8 or 9 dollars? "
"It is so hot today. It must be, what, 95 degrees out? "
"She moved to New York, what, 10 years ago? "
Is ‘what’ in these sentences similar with a tag question?
It’s been, what, five years! = It’s been five years, hasn’t it?
Yes, almost exactly the same. The meaning is identical, but maybe “,what,” has a connotation of surprise or emotion, while “hasn’t it” is more matter of fact.