"How many dead were there?"

Translation: Kolik bylo mrtvých?

[a-m-j]

Kolik bylo mrtvých tam? Why is it wrong?

[Weltreisender]

The 'there' in the question isn't referring to a place, but a state of past existence. 'There were XXX dead' as opposed to 'There (location), there were XXX dead.' So, the 'tam' in your answer isn't necessary.

[paulk1011]

But the way the question is written,'there' could be referring to a place. It could equally mean 'How many were dead?' or 'How many dead were in that place?'

[andresmdlc]

There is not way to know if there is place or "at that time". I also thought if was referring to some place

[deactivated user]

I wrote: Kolik mrtvých tam bylo? and it was accepted.

[LetitiateT]

It is wrong word order. "Kolik tam bylo mrtvých?" or "Kolik mrtvých tam bylo?" is OK.

[PritelBobka]

Is mrtvých a noun or an adjective in the genitive here? If a noun, what is the nominative form for this?

[VladaFu]

It is an adjective meaning "dead". The masculine nominative is mrtvý.