Reference for Bekhorot 10:4

ושמע מינה

And still further deduce from here, that the sixth part added, is a sixth of the total.<span class="x" onmousemove="('comment',' Lit., 'from outside'. I.e., to each five portions, one is added, an addition of twenty per cent. And here, also, there was an addition to the two hundred denar which constitute the sacred maneh of twenty per cent, making a total of two hundred and forty denar. This addition of forty denar makes therefore a sixth part of the sum total, i.e., a sixth 'from the outside', although not a sixth part of the value of the sacred maneh as such, as forty denar would be a fifth part of two hundred denar.');">³</span>

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