"The horse eats about ten apples."
Translation:Das Pferd frisst etwa zehn Äpfel.
Here's an interesting thing in German: animals don't have a Mund, they have a Maul. They don't Essen, they Fressen. Menschen essen mit dem Mund. Tiere fressen mit dem Maul.
fast means "nearly" meaning that the number is a bit less than what follows.
circa, etwa, ungefähr all mean pretty much "about, approximately" meaning that the number is close to what follows but may be a bit more or less as well.
To me, (a native U.S. English speaker) almost and nearly are synonymous, so I don't understand why using fast instead of etwa was marked incorrect. If I was talking to someone, wouldn't they understand what I meant?
Yes, "almost" and "nearly" are pretty much synonymous; you could translate them both with fast.
etwa, on the other hand, means "approximately" or "about".
If you used fast zehn Äpfel, you would indicate that the horse definitely ate fewer than ten apples -- maybe it ate nine whole apples and part of a tenth one, so it was "almost ten apples" or "nearly ten apples".
While if you said ungefähr zehn Äpfel or etwa zehn Äpfel (about ten apples), it means that the number was either ten or close to it -- could be nine, could be eleven. Perhaps you weren't counting exactly.
If the horse in fact ate eleven apples, then "about ten apples" (ungefähr zehn Äpfel) would be appropriate but "almost ten apples" (fast zehn Äpfel) would not.
And actually, if you look at the drop down menu translation for fast, it lists: almost, nearly, most...
Etwas - A previously undefined object (i.e "something"), as in "I want something, but I do not know what."
Etwa - "Approximately", as in "A walnut weighs approximately 100g".
I translated this as "Das Pferd frisst um zehn Äpfel", which was marked wrong as I did not include "die". Why is an article necessary there? .
It just is.
The usual way, with an adverb, is etwa zehn Äpfel or ungefähr zehn Äpfel, but another possibility is um die zehn Äpfel, in that case with die.
Without it, das Pferd frisst um zehn Äpfel would mean "The horse eats apples at ten" (i.e. at 10 o'clock).