1. 대충도 모르세요? Don't you know even not in detail?/even roughly? 2. 대충 하세요. Do it roughly. (You don't have to be careful about doing it)

1. 대충도 모르세요? this means....something like....come on, just finish it already! 2. 대충 하세요. so this would be like... just do it already. 대충 is what we can use to descrive something that is done in fast and rough way without having any neatness in qualities. 너무 대충 설명 했나요?