How to Write Right: Number Theory

Number Theory

We’re all familiar with the phenomenon of acronym redundancy, in which someone writes an acronym plus the spelled-out form of the last abbreviated word (e.g., “ATM machine,” which stands for “automated teller machine machine”). This occurs because people know what an acronym means but have lost track of what, precisely, the letters stand for. A less familiar variation of this mistake involves numbers instead of acronyms:

About a 1,000 people attended the event.

The problem here stems from a mingling of the spelled-out and numeral forms of the number. When spoken out loud, the number 1,000 is rendered as “one thousand” or “a thousand.” So when you write “a 1,000,” you’re actually saying “a a thousand.” But when we write numbers in numeral form, we can’t see the words we pronounce out loud, so we forget they’re there.

Something similar happens with fractions:

Each guest got 1/10th of the cake.

Here the suffix “th” has been added onto a fraction unnecessarily. When we write 1/10, we of course mean “one-tenth,” not “one-ten,” so 1/10th should logically be read as “one-tenthth.” Try saying that ten times, fast, next time you’re tempted to overcompensate for the invisibility of letters or words in numeral forms.

Illustration by Andrew Saeger for City Arts.