Puzzle: The Chinese Farmer

A Chinese landowner wanted a farmer to work for 6 days for him. The reward: a slab of gold. The price: solving a riddle.
"I'll pay you per day: after day 1, you'll have one sixth of the gold, the next, two-sixths, et cetera, until after 6 days, you have the entire slab of gold. How do I do that, though?"
"Easy. Cut the slab into 6 equal parts, and give me one part each day."
"Ah", said the landowner. "But you can only cut the slab twice."
"Pff", said the farmer. "Still easy."

(Use rot13 to see the solution)
"Phg gur fyno gjvpr gb perngr guerr cvrprf: bar cvrpr (N) gung vf bar fvkgu bs gur fyno, bar (O) gung vf gjb-fvkguf (bar guveq) naq bar (P) gung vf guerr-fvkguf (unys).
Ba gur svefg qnl, tvir zr cvrpr N.
Ba gur frpbaq qnl, tvir zr cvrpr O naq V'yy tvir lbh onpx cvrpr N.
Ba gur guveq qnl, tvir zr cvrpr N onpx. V abj unir cvrprf N naq O, juvpu gbtrgure ner guerr-fvkguf.
Ba gur sbhegu qnl, tvir zr cvrpr P naq V'yy tvir lbh cvrpr O. V abj unir cvrprf N naq P, sbhe-fvkguf.
Ba gur svsgu qnl, tvir zr cvrpr O naq V'yy tvir lbh cvrpr N va erghea. V abj unir cvrprf O naq P, svir-fvkguf.
Naq svanyyl, ba gur fvkgu qnl, tvir zr cvrpr N naq V unir nyy guerr cvrprf, gur ragver fyno bs tbyq."

Needless to say, the landowner hires the farmer and retains him at a nice wage for the rest of his life.