"Excuse me! What day of the month is it today?"
Is it unacceptable/uncommon to say this with "是" included?
"请问，今天是几号？" is what I put.
That is what I put, as well, especially since '今天是 . . .' has been accepted on previous sentences, so input from a native speaker would be helpful, here.
'几月' is not needed in this translation because the speaker already knows what month it is. If the sentence were to be asking for today's date rather than today's number (what day of the month today is), then the inclusion of '几月' would be necessary and correct.
Sometimes "excuse me" is translated as "不好意思". Can it be a correct answer in this case? “不好意思，今天几号？”
I think 不好意思 (buhaoyici) is used in a different context, it has an embarrassed, "sorry to inconvenience you" feel/meaning to it. So I guess it would apply here, but like, depending on the context.
There isn't any interrogative word. Is that not strange?
Is it just a way to speak, or is there any grammatical rule?
几 ji is the question word in this for asking dates, according to the lesson.
Apparently, "请问今天号多少" is incorrect. I thought this might be valid in analogy to the question for the phone number. Any thoughts?