Good morning, Hank; it's Sunday, February 22, and today I am going to present you with real, unassailable evidence that oil companies are ripping you off... through the evil magic of demon mathematics.

Now, Hank, before we start, I wanna say for the record that just because oil companies are ripping us off does not mean that gas is too expensive. In fact, Hank, even at the very height of the 2008 oil bubble, a gallon of gasoline was still less expensive than a gallon of Fierce Grape Gatorade. Which strikes me as just a little bit odd, since oil must be mined from the depths of the earth, shipped across the world, then refined, then trucked to a gas station and sunk into a gigantic underground container... whereas to produce Fierce Grape Gatorade, I believe all you have to do is milk purple alligators.

But all that said, I've never been able to shake the suspicion that oil companies were ripping me off, and it turns out I am totally right! Okay, Hank, so I believe you and I both have the same third-grade teacher, Miss Fink, and so you may remember when Miss Fink taught us the rules of rounding; you know, if you're rounding to the nearest whole number, 4.6 becomes 5, 4.4 becomes 4, et cetera. Miss Fink, of course, taught us that you round 1 to 4 down and 5 to 9 up... well, Hank, it turns out that Miss Fink was a dirty liar in cahoots with Big Oil.

Because if you round 1 to 4 down and 5 to 9 up, you end up rounding down four-ninths of the time and rounding up five-ninths of the time. There is, actually, a fair system of rounding called Dutch rounding, in which you round 1 to 4 down, 6 to 9 up, and then you round 5 up or down based on the numbers around it. But when it comes to the fractional pennies in your gasoline purchases, you will never guess which system of rounding the oil companies use... unless you guessed that they use the one that gets them the extra penny one-twentieth of the time.

That's right, Hank, 5% of American gasoline purchases are charged an extra penny because of stupid, unfair, third-grade rounding! Now I know what you're thinking, Hank; you're thinking... say I go to the gas station once a week, that means on average I lose about two-and-a-half pennies per year. Well, first off, it's not two-and-a-half pennies; according to the oil companies, it's three pennies.

And second off, it's actually millions of dollars every single year. Hank, the whole "oil company stealing people's money via rounding" reminds me of something that Abraham Lincoln once said. He said, "You can fool some of the people all the time, and all the people some of the time, but you can't fool all the people all the time"... unless it's a question of math, then you can, in fact, fool all the people all the time.

So, Hank, that's this week's installment of "Why Mathematics Matters." I did some calculations, and even though I haven't owned a car for a lot of my adult life, Exxon owes me about eight pennies. So I wrote them a letter explaining the rules of rounding that they've been exploiting for decades and asked for my eight cents back. I'll let you know how it goes.

Oh, and Hank, you may be wondering why Dutch rounding is called Dutch rounding... allow me to read to you from Wikipedia: "The term 'Dutch rounding' originated during the Dutch Golden Age. This period of wealth was characterized by opulent feasts where many prominent Dutchmen grew round." [bounces happily in chair] Oh, Wikipedia, with your tension between those who would share knowledge and those who would destroy it.