1)
What is "Tachtim Chadshi"?
1.
Rashi: It was a newly settled place with few residents. Yo'av hoped that amidst this David will [hear that the population is small, and] retract 1 [from his command to count Yisrael].
2.
Targum Yonasan: A southern land, Chadshi. Radak - I do not know why he translated so.
1
Kli Yakar: Yo'av went to places that one would not think to go there, in order to delay, hoping that in the meanwhile, David will retract. (David commanded to count all of Yisrael. Why should any place be omitted? - PF)
2)
What is "Danah Ya'an"?