Translation:It takes ten days.
There are special pronunciations for counting days of the month, particularly 1-10, 14, 20, and 24. You can find the complete chart here: https://www.learn-japanese-adventure.com/image-files/t3-japanese-days-of-the-month.png
For the day counter, the tenth is pronounced tooka (too is pronounced like toe in English). To remember it, I think of ten toes.
On the tiles, 十 is pronounced じゅう and 日 にち。Although those readings would be correct in other contexts, here 十 should be pronounced とお and 日 should be か.
If Duolingo isn't able to pronounce the kanji correctly, it would be helpful to have the hiragana at least to help us learn proper pronunciation.
I think "十日" of "十日かかります" is enough.
Because the verb is "かかります". It is fit "take". ("かかる" already imply it is "a period/term".)
Though I sometimes hear "十日間かかります。". Because it is not so strictry in conversation.
This person explained in detail. S/he insists that "十日かかります" is correct.
I can not find another comment now.
The link is useful (though I only somewhat understood the explanation in Japanese)! I always thought: 三時 = 3 o'clock 三時間 = 3 hours Therefore 三日 = the 3rd day of a month 三日間 = 3 days
It is not!! (mind blown) 三日 = 3 days OR the 3rd day of a month 三日間 = in the duration of 3 days
So 十日 can be a duration, while 十日間 refers to within the period... or something. I worry about counting months and years now.
If you say 'じゅう', it is ten.
When you asked about 'じゅうにち', It had 'にち'. 'にち' is about 'date'. But you ask the case what 'when not refer to the date'. So I don't have an answer to the question. 'じゅうにち' is a just incorrect word. Native speakers don't use the word. At least I have never heard to use by adults. I hope your help. :)