Before the recent decimalization, U.S. securities prices were quoted in binary fractions of dollars. Because the options contracts in question referred to 100 shares, a price of, for example, "3'4" translates into a cost of $325 per contract. A `July/40 call" gave the right to buy 100 Polaroid shares at $40 per share at any time up to its July expiration date.

Donald MacKenzie, An Engine, Not a Camera, loc. 1408