How to read 二、三日 [duplicate]

Question

If you have the two separate words, it's 二日{ふつか} and 三日{みっか}. But how are they read together? ふた、みっか, に、さんにち, some combination thereof or something else entirely?

Source sentence for the curious:

アキちゃんは広いお屋敷で二、三日ゆったり過ごしてくればいいのよ。

Answer 1

It is read 「にさんにち」.

Colloquially, people say 「にさんち」 as well.

Answer 2

It reads に、さんにち (the comma is purely orthographic, you may or may not write it out).

Similarly, we say...

一、二日　いち、ににち
三、四日　さん、よっか ← irregular!
四、五日　し、ごにち
五、六日　ご、ろくにち

Longer span equivalents are hardly heard, perhaps because we come to use "a week" (一週間) or other higher units then, I suppose.

ふた、みっか might actually sound surprisingly comprehensible to native speakers, but it never exists.