Thirdsday: the Holiday That’s 33.33…% Better Than Any Other

Begin the festive countdown, folks, because tomorrow is Thirdsday!

Invented/discovered by the visionary Jim Propp, this holiday celebrates the extraordinary fraction 1/3. It comes, on average, only once every seven years, when the third day of the year (1/3 in the U.S.) falls on a Thursday.

Thus, Thirdsday is like a rare cicada, except less noisy and regular. It’s like a solar eclipse, except more blinding and wondrous. It’s like an Alfonso Cuaron film, except 100% scientifically accurate.

In short: It’s like Pi Day, if Pi Day were still cool and indie.

You can see Thirdsday coverage from mathematical luminaries like Evelyn Lamb, James Tanton, William Gasarch, and Matt Parker. For my part, I wish to briefly make the case that 1/3 is vastly superior to its feeble little brother 1/4.

“Yes,” you say. “It is bigger.”

But have you considered how much bigger? And more to the point, have you used fraction of the day spent sleeping as your unit?

2018.9.10 quarter vs. third.jpg

“What buffoon would mistake these two fractions?” you ask. Well, my mathematical countrymen, the answer is simple and sad: my American countrymen would.

Consider (from Mental Floss) the tragic tale of the A&W Restaurant’s “third-pounder” burger.

In the 1980s, A&W attempted to capitalize on the success of the [McDonald’s] Quarter Pounder… by introducing a third-pound burger. The bigger burger… was priced the same as the Quarter Pounder but delivered more meat. It even outperformed McDonald’s in blind taste tests…

But sales lagged behind the quarter-pounder. Why? Alfred Taubman, owner of A&W and author of Threshold Resistance, explained:

More than half of the participants in the… focus groups questioned the price of our burger. “Why,” they asked, “should we pay the same amount for a third of a pound of meat as we do for a quarter-pound of meat at McDonald’s? You’re overcharging us.” Honestly. People thought a third of a pound was less than a quarter of a pound. After all, three is less than four!

Redeem yourself, America.

Help us, world.

Join me in celebrating the holiday consecrated to the beauty and superiority of 1/3.


13 thoughts on “Thirdsday: the Holiday That’s 33.33…% Better Than Any Other

    1. I don’t think you can blame the metric system for American innumeracy, especially in the 1980s. In fact, it probably would work the other way: If McDonalds had been selling the 0.113-kg-er and A&W had introduced the 0.151-kg-er, there would have been no issue.

  1. I understand the confusion on the burgers… I routinely try to order “a third of a pound” of deli meat or cheese at the supermarket. I usually clarify by saying “about point-3 to point-4 of a pound” and often get a completely different amount. I don’t bother explaining that 0.3 and 0.4 are not the same as 1/3 and 1/4… sigh.

  2. As Gregorian calendar repeats after 400 years .. or 4800 months.
    days of week never divides equally by any birthday.
    Distribution of 1/03.
    When is highest yr/400 IF 1/3/400 occurs exactly 1-7th of the time?

  3. A few years ago, we had a local restaurant chain in Oklahoma (Braum’s) advertise their 1/3 pound burger was 1/3 larger than a quarter-pounder. I was proud of the mathematical awareness of their advertising department, but as you implied out above, that’s a little too many fractions for the general public.

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