3,457. Those Who Sell by Approximation
Hilchos Maaser 11:3
A large quantity is half a seah in dry measure (about 1.25 gallons) or a dinar’s worth of a liquid in liquid measure.
Hilchos Maaser 11:4
Even if someone sells baskets of olives and grapes or containers of vegetables by approximating their volumes, he may not sell them as demai.