The Punctuation of Maths

I do love a bit of cross-curricularism. Although maths will always be my first love, I must admit to being passionate about language too. One of my (many) skills is being able to identify the Latin/Greek/Whatever root of a word and explain the original meaning. Actually, that's just given me an idea for another post...

But anyway, this post isn't about words, it's about punctuation. I am still quite confused about when to use commas, semi-colons, colons, emdashes, endashes etc, although I do find them interesting. Language is very mathematical when you think about it.* But I'm not talking about English grammar here (which is probably a good thing, as I began this sentence with a conjunction), I'm talking about the punctuation of maths.

All of you reading this now, write down what a half is as a decimal. Have you all done it? Yes, even you. Good. Now, type what you just wrote into the search bar on your browser's toolbar (assuming you have one) without pressing enter. If you prefer, type it in a Notepad file. Done? OK.

Compare what you have written and typed. Are they the same? Look specifically at the decimal point. I'm guessing all of you used a full stop for your typed version. What about your handwritten version? Is your point at the bottom, resting on the line, or hovering in the middle? (Some of you may have used a comma instead. I'll get to you later).

In the US, it has always been the norm to use a full stop (or as they call it, a "period") as the decimal mark. So we can assume this is wrong. Kidding! (I have a few readers from the US who I must try not to insult). In Britain (and in British Empire nations) however, the mid dot, or "interpunct", was the standard symbol. However, the full stop was OK to use in typing and printing. The mid dot can be easier to read on lined paper because the point can't be hidden by the line.

There is a problem with the mid dot though. To me, such a mark indicates multiplication (although as far as I can tell this is never used in schools), and the top guys at the SI agree, because they rejected it as the standaard decimal mark.

In the end (well, in 2003), The 22nd General Conference on Weights and Measures declared that "the symbol for the decimal marker shall be either the point on the line or the comma on the line" (yes, comma users, I'll get to you), meaning that officially decimal points and full stops have the same appearance. Some older British people may angrily disagree with this decision. For once I'm not bothered.

OK, the people I was ignoring: some people use commas instead of dots for the decimal mark. Namely, people from non-British Europe, and also some random places like South Africa. This is because originally, a short, vertical mark dash was used as the decimal mark. This evolved into either the comma or the dot. France preferred the comma (presumably because it's more phallic) and the rest of Europe then took sides.

Now, some more writing for you to do. Write down, in figures, the number twenty seven million, five hundred and sixty four thousand, two hundred and fourteen. Done? Good.

Look between the seven and the five. What's there? A comma? A gap? Nothing? (For the Europeans: a dot?)

I was always taught at school that you should just leave a space between every three digits, and not put a comma. I had a few reasons given to me for doing this: because a comma could get confused with a decimal point (really?) or because Europeans might think it's a decimal (fair enough). Because I was taught this in school, I get really annoyed when I see people using commas. It's not what you're supposed to do!

I have researched this to check that I am correct, and I have found that the International Bureau of Weights and Measures states that "for numbers with many digits the digits may be divided into groups of three by a thin space, in order to facilitate reading. Neither dots nor commas are inserted in the spaces between groups of three". Officially this space is supposed to be a half space, although I don't know how to do that on MS Word.

I think most maths teachers in the UK would know better than to use commas to separate digits (they jolly well should!) but non-maths teachers may not know this rule or appreciate the importance of it and hence you might find commas in long numbers in Geography lessons. It should be part of a school's numeracy policy that every teacher conforms to this. Otherwise it would be as bad as a non-English teacher using an aberrant apostrophe (which I'm sure NEVER happens). I fully realise that by saying this I am practically begging people to criticise my grammar on this blog. Bring it on!!!

I will leave you with a nice little anagram puzzle:
Rearrange this expression to make another one: "I'm a dot in place".

Emma x x x


*One punctuation thing that annoys me because of its lack of mathematical sense is the " quotation mark. In a book, if someone is talking for a long time, there can be a paragraph break in the middle of their speech. You do not close the speech marks at the end of the paragraph, but you do have to put an open speech mark symbol at the start of the next paragraph. This annoys me because it's like having an open bracket that is never closed. In programming, such a thing is, to my knowledge, always disallowed.