Terumot, Chapter Four, Mishnah Thirteen
Rabbi Yose said: A case once came before Rabbi Akiva concerning fifty bundles of vegetables into which a bundle of the same size had fallen, half of which was terumah.
And I said in front of him, that it can be brought up, not because terumah can be brought up in fifty-one, but because there were one hundred and two halves there.
The issue in this case is how do we look at the fifty bundles of hullin vegetable into which one bundle of vegetables, half of which was terumah, has been mixed? Is this a case of fifty one bundles, in which case one would not be able to remove one bundle, give it to a priest and consider the rest to be hullin? Or do we simply look at the total amount of hullin and the total amount of terumah, in which case there is sufficient hullin to allow one to remove one half of one bundle, give it to a priest and keep the rest as hullin?
Rabbi Yose teaches that we take the latter optionwe look at the total amount of vegetables and not the number of bundles.