## How to Remember a Round Number

A traditional French rhyme goes like this*:

Que j’aime a fatre apprendre

Un nombre utile aux sages!

Glorieux Archimede, artiste ingenieux,

Toi, de qui Syracuse loue encore le merite!

( * A loose translation is:

How I like to make

The sages learn a useful number!

Glorious Archimedes, ingenious artist,

You whose merit Syracuse still praises.)

But to which ‘number useful to the sages’ does it refer? Counting the letters in each word, treating ‘j’ as a word with one letter and placing a decimal point after the first digit, we get

3.141 592 653 589 793 238 4626

which is $\pi$ to the first 22 decimal places. Many similar mnemonics for $\pi$ exist in many languages. In English, one of the best known is

How I want a drink, alcoholic, of course, after the heavy

chapters involvlng quantum mechanics. One is, yes,

adequate even enough to induce some fun and pleasure

for an instant, miserably brief.

It probably stopped there because the next digit is a 0, and it’s not entirely clear how best to represent a word with no letters. Another is

Sir, I bear a rhyme excelling

In mystic force, and magic spelling

Celestial sprites elucidate

All my own strivings can’t relate.

An ambitious $\pi$ -mnemonic featured in “The Mathematical Intelligencer” in 1986 (volume 8, page 56). This is an informal “house journal” for professional mathematicians. The mnemonic is a self-referential story encoding the first 402 decimals of $\pi$. It uses punctuation marks (ignoring full stops) to represent the digit zero, and words with more than 9 letters represent two consecutive digits — for instance, a word with 13 letters represents the digits 13 in that order. Oh, and any actual digit represents itself. The story begins like this:

For a time I stood pondering on circle sizes. The large

computer mainframe quietly processed  all of its assembly

code Inside my entire hope lay for figuring out an elusive

expansion. Value pi. Decimals expected soon. I nervously

entered a format procedure. The mainframe processed the

request. Error. I again entering it, carefully retyped. This

iteration gave zero error printouts in all — success.

You can find out more about $\pi$ related mnemonics in various languages please use the internet.

More later,

Nalin Pithwa

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