H E L L O
my name is
Dr. Shapiro's Puzzle of the Day

Today's Puzzle

Tuesday, May 4

Tax code may be complicated, but there is usually an underlying logic to it.

Can you deduce the exact number I have blacked out in this table from an IRS publication?
(Feel free to use a calculator.)

   


     Note: Clicking "Submit" will send your response to Dr. Shapiro.

Yesterday's Puzzle + Solution

Your local library probably uses the Dewey Decimal System to organize books by subject. Books are numbered from 000 to 999, with the hundreds digit indicating a major area of knowledge, the tens digit a subdivision, and so on. For example, books about heredity are filed under 575.1:

The emoji on each line above are, of course, not an original part of Melvil Dewey's system; they were created by the website LibraryThing, which gives the "Dewmoji" path to 575.1 as 🔬 > 🧬 > 🌱 > 👪.

Now, 🌱 could just as easily be botany or horticulture; there aren't enough emoji to give every subject a unique and fitting symbol. Hence this puzzle! I'll give you some Dewmoji paths—you guess the subjects. For example, if I hadn't told you what 🔬 > 🧬 > 🌱 > 👪 is, a reasonable guess might be "Science > Biology > Plants > Plant Families". To help you out, I'll give you a sample book title at the end of each path. Let's go!

1.    🔬 > 🐼 > 🐚 > 🐙        Sample book: Inky's Amazing Escape
2.* 🔬 > 🍎 > 🌈 Sample book: Molecular Vibrations: The Theory of Infrared and Raman Vibrational Spectra
3.* 🙏🏽 > 📖 > 🌈 Sample book: Why Noah Chose the Dove
4. 💭 > 🔮 > 🤓 > 🦆 Sample book: Exploring Atlantis Related Through the Soul of Rev. Dr. Frank Alper
5. 💭 > 🚎 > 🙈 > ⚖ Sample book: Raise the Bar: Real World Solutions for a Troubled Profession

*Tip: The rainbow is used for two unrelated subjects.

Solution
  1. (594.5) Natural sciences and mathematics > Zoology > Mollusks > Cephalopods
  2. (535) Natural sciences and mathematics > Physics > Optics
  3. (221) Religions > Bible > Old Testament
  4. (133.7) Philosophy and Psychology > Parapsychology And Occultism > Specific Topics > Humbugs; Quackery
  5. (174.3) Philosophy and Psychology > Ethics > Professional and Business Ethics > Lawyers

There's no list of solvers today, since this puzzle is basically unscorable. But I hope you had fun!

About This Site

Though he now teaches mathematics, Dr. (né Mr.) Shapiro's first job in a K–12 school was as a lunch monitor in Davis, CA. It was there that he originated the Puzzle of the Day, even rewarding correct answers with tickets in denominations like "15 points" (though without a clear idea of how he'd ultimately redeem these). Dr. Shapiro's favorite puzzle from this pre-professional era was "Tell me the location of the beehive on this campus."

Ten years later, Dr. Shapiro revived Puzzle of the Day at Proof School, writing each day's puzzle on a name tag. After 600 puzzles or so, he was just starting to feel normal about students reading his chest all the time when campus closed and the puzzle, like the rest of our lives, moved online. New puzzles are posted daily on school days.

Want to catch up on old PotDs? There's an archive currently containing puzzles from March 2020 to March 2021.