SB 10.90.42
sankhyanam yadavanam kah
karisyati mahatmanam
yatrayutanam ayuta-
laksenaste sa ahukah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Who can count all the great Yadavas, when among them King Ugrasena alone was accompanied by an entourage of thirty trillion attendants?
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Srila Visvanatha Cakravarti explains why specifically thirty trillion, rather than an indefinite number of tens of trillions, is stated here to be the number of King Ugrasena’s attendants. He does so by citing the interpretational rule of kapiñjaladhikarana, the logic of “referring to pigeons”: Somewhere in the Vedas is found the injunction that “one should sacrifice some pigeons.” This plural number should be taken to mean not an indiscriminate number of pigeons, but precisely three of them, since the Vedas never leave any matter vague. The rules of Mimamsa interpretation take three as the default number when no specific number is given.