Mnemonic Metric Prefixes

By The Metric Maven

Integer Solar Orbit Day

Engraving of Kilroy on the WWII Memorial in Washington DC

Years ago, my friend Ty took an interest in how to remember information. He pointed out that often you will think of something you want to do or retrieve, leave the room where you made the decision, and by the time you arrive in the next room, have forgotten. Often you return to the the original room, and then suddenly can recall what you meant to retrieve or view. Ty asserted it was because you had associated the decision with the original room, and when you returned, the two things were attached in your mind and you immediately recalled why you left in the first place. Years ago, when I was a young boy, people would tie a string around their finger to remind them to remember an important piece of information.

When I was taking trigonometry in high school, the teacher indicated we should remember words and phrases to recall the definitions of the sine, cosine, and tangent of a right triangle. He offered:

The adjacent side of the triangle was closest to the angle, the opposite side was well, opposite of the angle, and the hypotenuse was the long side that was not the others. Silly Cold Tigers? and Oscar Had A Happy Old Aunt?—how ridiculous!—but decades later, I still remember this method of recalling the definitions of the basic trigonometric functions of a right triangle. He encouraged his students to make up their own, and indeed they came up with more memorable phrases that were the sort that teenage boys were more likely to remember.

A number of “metric advocates” have ridiculed my assertion that grade school children, middle school students, and high school pupils, should be instructed in the use of all the metric prefixes. In my view, all the prefixes means the eight magnifying and eight reducing prefixes separated by 1000. One of the most effective instructive methods for recalling information is the use of a mnemonic device. Here I propose a pair of these, one for the magnifying prefixes, and one for the reducing prefixes. The first mnemonic is presented in the table below for the magnifying prefixes:

The mnemonic phrase for the magnifying prefixes is: “Kilroy Might Get To Paris Escorting Zombies Yonder.” The first letter of each word corresponds to the prefix symbol. The first prefix is Kilo is suggested by the name Kilroy, but the rest of the prefixes all end with an “a.” This can be thought of as the prefixes “above” unity.

The second table for the reducing prefixes is:

The mnemonic phrase for the reducing prefixes is “Millie might not protest fetching another zesty yeti.” Again the first letter of each word corresponds to the prefix symbols except for micro. The student would have to spell out micro and then recall the μ symbol is used, rather than another m. The first word is again a name, Millie, which in this case contains the spelled out prefix. Again means we need to forget it, but realize the reducing prefixes all end with “o” and are “below” unity.

In both cases the phrase begins with a name, and involves that person compelling mythical creatures.

If students were taught these mnemonics from perhaps grade 6 or 7 onward, with metric prefix examples, like those found in The Dimensions of the Cosmos, by the time they graduated from high school, they could have the tools needed to recall the metric prefixes without a textbook, and be reminded to use them in their work.

I would be interested in any comments or suggestions readers might have about these proposed mnemonic devices that might improve them. The best way to promote their use would be for the US to become a mandatory metric nation, but as this country celebrates its reactionary nature with religious fervor, I’ll have to settle for whatever good these mnemonics might do without a change.


If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.

Spelling Out Metric

Chang Apana – The “real” Charlie Chan

By The Metric Maven

Mind, like parachute, only function when open. — Charlie Chan

My interactions with English pedants has generally been filled with friction. They offered spelling rules which are clearly arbitrary and somehow link the ability to regurgitate these strings of letters with intelligence. Take for instance the number 4 is spelled four, but the number 40 is “correctly” spelled forty. One web page of pedantic rules reminds the reader:

When writing out numbers between forty and forty-nine, be sure to remember that forty has no u in it (this is a common spelling error).

Is something really an error when it makes no logical sense, and such rules appear  to have sprung out of an intellectual vacuum? Let’s change the spelling of 40 to fourty and have it make sense. Is the spelling color or colour more intelligent? Program or programme? The British might have some input on this.

I was recently reading the interesting book, Charlie Chan, by Yunte Huang, who has a PhD in English. One expects with that background, his prose will conform to the most up-to-date standards of our American English grammar. A paragraph in the book stopped me in my tracks:

Overlooking any questions of the viability of this computation, I realized that when I hit:

“…with more than 250 sugar plantations in Louisiana and Mississippi, the aggregate yield was only twenty-five million pounds in 1866. By contrast, Hawaii’s mere twenty-nine small plantations yielded a total of twenty-seven million pounds in that year.”

I had no idea what the magnitude of the numbers were. The concatenation of the two spelled out quantities, sandwiched between the number of Hawaii’s plantations left me bereft of numerical information.

I had an immediate flash-back to a lesson my High School English teacher imparted. She was adamant that when writing proper English prose one spells out numbers, and does not introduce numerals. At the time, I didn’t really think much of it, after all, a spelled-out number is as cognitively understandable as a Hindu-Arabic expression?—Right?

After a considerable number of solar orbits, I began to question this assumption. When I read this passage, I became convinced that spelling out numbers was an arbitrary “rule of English grammar” that served to allow one to readily read the prose, and lose the numerical content.

On one style page I found online, asserted there are rules for “regular folks” and those for when it involved “scientific writing.” This is the same odoriferous BS used in the US to say that Ye Olde English measurement is for “regular folks,” and metric is only for “science.” This is simply absurd and promotes innumeracy. Over 190 countries would probably also demur.

Take the value twenty-seven million pounds. We can first write it as 27 million pounds. The numerical representation uses two symbols to convey the same information that prose requires 12. The hyphen is to tie the two words twenty and seven so you realize it is a single number and not 20, 7. We have a Ye Olde English modifier of million, which when written out would be 27,000,000 pounds. I’m assured by English pedants that the commas are “proper” which demonstrates that grammar rules are but monuments to some mythological tradition devoid of introspection, and not an enlightened scientific one.

Perhaps we could write 27 million pounds using the metric system as: 12 Gigagrams and 25 million pounds as 11 Gigagrams. Now if the quantities in the sentence are written numerically, rather than alphabetically we obtain:

“…with more than 250 sugar plantations in Louisiana and Mississippi, the aggregate yield was only 11 Gigagrams in 1866. By contrast, Hawaii’s mere 29 small plantations yielded a total of 12 Gigagrams in that year.”

Wow, look at that! The numbers all seem to stick to their respective nouns and provide easy comparison. I can see that just under 10 times as many plantations were needed on the mainland to match about the same sugar output as those found in Hawaii !

I have been accused many times of being verbose with my prose. Sadly, the evidence is generally on the accuser’s side. Wordiness is indeed undesirable, and I struggle to prune my sentences. Wordnik defines wordiness thus: “The excessive, often unnecessary, use of words in a sentence.” Why is it that no English pedants have an objection to being verbose when expressing numbers? It is argued in one style guide that: “It is generally best to write out numbers from zero to one hundred in nontechnical writing.” So it is better to write out eighty-seven Kilograms, than to use 87 Kg in a sentence? Seems verbose to me. What may be easy to read, does not translate into ease of cognition. The practice of writing out numerals alphabetically often inhibits “reading comprehension” in my view, which English pedants also use as an important metric.

Hindu-Arabic numerals have such a polluting effect on English prose according to the pedants, that no sentence is to begin with one. So

Seventeen seventy-six was the year America became a nation.

is a correct sentence, but,

1776 was the year America became a nation.

is an abomination of the written form of The (definite article) English language. One must have a word first, such as:

In 1776, America became a nation.

That is a shorter sentence with the number assumed to be a year, but a clarification is spelled-out (literally) in the previous sentences. One loses a clarification in the sentence above. It could be re-written:

In the year 1776, America became a nation.

instead, which is a lot of extra effort to prevent a Hindu-Arabic number from starting a sentence, when both sentences have the same number of words and numbers.

My interest is to present numerical information in written prose in a manner that provides the easiest cognition. If the “rules of grammar and style” try to interfere, I will gladly slay them for clarity. Winston Churchill made himself quite clear on this point when he said: “Ending a sentence with a preposition is something up with which I will not put.”


If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page and contribute. Also purchase his books about the metric system:

The first book is titled: Our Crumbling Invisible Infrastructure. It is a succinct set of essays  that explain why the absence of the metric system in the US is detrimental to our personal heath and our economy. These essays are separately available for free on my website,  but the book has them all in one place in print. The book may be purchased from Amazon here.


The second book is titled The Dimensions of the Cosmos. It takes the metric prefixes from yotta to Yocto and uses each metric prefix to describe a metric world. The book has a considerable number of color images to compliment the prose. It has been receiving good reviews. I think would be a great reference for US science teachers. It has a considerable number of scientific factoids and anecdotes that I believe would be of considerable educational use. It is available from Amazon here.


The third book is called Death By A Thousand Cuts, A Secret History of the Metric System in The United States. This monograph explains how we have been unable to legally deal with weights and measures in the United States from George Washington, to our current day. This book is also available on Amazon here.

If you liked this essay and wish to support the work of The Metric Maven, please visit his Patreon Page.