1)
Who did not make a calculation?
1.
Rashi: The Amerkalim (overseers) did not make a calculation with the Gizbarim (treasurers of Hekdesh) 1 . The Amerkalim constantly give money to the workers; they were not suspected.
1
Radak citing Bava Basra 9a: Chazal expounded from here that we do not calculation with Gaba'im of Tzedakah. We appoint proper people; we do not suspect their integrity.
2)
How was it known that they do honestly?
1.
Radak: They were trustworthy.
