's :: Two 9's or Two 9s

Dear teachers,

In plural, as in:There are two 9 in 99; 2 VIP; in the years 1980; pronounce two r clearly…

You’ll write:

Two 9’s or two 9s
Two VIP’s or two VIPs
1980s or 1980’s
two rs or two r’s


PS: Does 1980s means in the years 1980 (including1980,1981,1982,1983,1984,1985,1986,1987,

Hi Quoc

To make plural forms for these sorts of things, sometimes an apostrophe is used and sometimes not. There seems to be some disagreement on the “rule” here.

But I’d say if the plural could be easily misread/misunderstood (as is the case with “rs”), then you should use the apostrophe.

Saying “in the years 1980” is wrong. You should not use this expression at all.

Saying in the 1980s would include the years 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988 and 1989.
It does not include 1990.