1)
What is the meaning of "he counted them b'Vazek"?
1.
Rashi (from Yuma 22b): He took a shard from each (for one may not count Yisraelim directly).
2.
Rashi (from Tanchuma Ki Sisa 9): He took a rock from each [and counted the rocks]. Radak - the Targum of "ki'Tzror Even b'Margemah" (Mishlei 26:8) is 'Heich Bizka d'Kipa b'Kil'a.' 1
3.
Rashi: It is the name of a place - "Adoni Vezek b'Vezek" (Shoftim 1:5).
1
The Targum printed in our texts is 'Heich Niktza d'Tasa b'Kil'a.'
QUESTIONS ON RASHI
2)
Rashi writes that he counted them via shards or rocks. Why did he count them via lambs below (15:4)?