Apostrophes and Numbers
In elementary school, I was taught that to make a number plural, you use ‘s, not just s. So, if you talk about a particular decade, for instance, you would call them the 80’s. This rule also applied if, say, you wanted to talk about the Four W’s. (It’s a journalism term.)
But elementary school is also where I was taught to never, ever, ever begin a sentence with and or but, and I’ve written posts about how that has never been true, according to all authoritative sources on the subject. Neither has this.
The apostrophe, when not used in a contraction, indicates possessive. Clearly, neither of these cases involves possession. Therefore, the apostrophe should not be used. You would talk about the 80s or the Four Ws. I know, it looks weird. Change always does at first.