Questions about unknown people or things

Question

In my grammar textbook, under the title “Questions”, it’s stated that we don’t use “do, does, did” at the beginning of a questioning sentence, when the subject is “who/what etc.” For example:

“Somebody called Donald.”

So if we want to ask about the above statement the correct way of asking is:

“Who called Donald?"

Not: “Who did call Donald.”

So in this way if I wanted to make a questioning sentence from the following sentence:

“About one-hundred people came to the ceremony.”

I would have to ask:

“How many people came to the ceremony?”

But it sounds unnatural to me. I think the correct way is:

“How many people did come to the ceremony?”

Which one is correct?

Answer 1

A simple enquiry about numbers would be

How many people came to the ceremony?

However, if you said that (say) 50 people came to the ceremony and somebody said "that's wrong", you could then ask:

[So,] how many people did come to the ceremony?,

with spoken emphasis on "did".

Answer 2

If someone said "A lot of people came to the ceremony", you could ask "How many?" (or "How many people?" or "How many people came to the ceremony?").

But if someone said "About one-hundred people came to the ceremony", you probably wouldn't ask "How many?" (nor "How many people came to the ceremony?"), because there's a good chance they'd reply, "Like I told you - about a hundred."

So if they'd said "About one-hundred people came to the ceremony", you'd probably seek an exact number by asking "How many exactly?" or "How many precisely?" or "Do you know the exact number?". But if you were posing your question to someone else, you might simply ask "How many people came to the ceremony?".