[Avodah] arithmetic question

[Chesky Salomon]

The ranges in which ona'ah applies are determined like this
(formatting corrected):

* one-sixth of the starting price --
    1/6 * 210 = 35, so both 210 + 35 = 175 and 210 - 35 = 245 are ona'ah.

* one-sixth of the final price --
    6/5 * 210 = 252 --> 1/6 * 252 = 42 = 252 - 210, so 252 is ona'ah; and
    6/7 * 210 = 180 --> 1/6 * 180 = 30 = 210 - 180, so 180 is ona'ah.

(It has been pointed out to me that this does not in fact answer RET's
question regarding why milgav & milevar would apply simultaneously.)

--Chesky