I had back-to-back interesting number issues while filling my gas tank recently. (I also have a gas tank that refuses to let the pump run until it gets full, but that’s another issue.)
First, I got caught in a “nine-tenths” trap when I could have either an exact number of gallons or an exact amount of payment. That fraction turns out to be worth about three-thousandths of a gallon.
But it’s the second one that I’ve never seen before, and may never see again. The price did not end in nine-tenths of a cent, but six-tenths. On the board outside, it still said $1.999 — I had a 1-cent discount — but the digital pump readout said differently. The difference saved me all of three cents.