Num Numbers, chapter Book of Numbers, chapter 1
Take ye the rosh (top amount, census) of kol Adat Bnei Yisroel after their mishpekhot, by the bais of their avot, with the number of their shmot, every zachar by their head count; Exo 30:12From twenty years old and upward, all that are able-bodied to serve in tzava b'Yisroel (army in Yisroel); thou and Aharon shall number them by their tzva'ot (legions).1Ch 25:28; 2Ch 25:5