What is the best plural of "+1" in casual American English writing?

Possible ideas I've considered include:

  • +1s
  • +1's
  • this is a duplicate. use the search.
    – vectory
    Dec 23 '19 at 19:53
  • The main sense of +1 is the operation, 'add one', which can't have a plural. If you mean the numeral [positive one], it has a plural when used 'as a word'. Italics and the apostrophe would be used, so +1's, to distinguish it from + 1s meaning + one second. Dec 23 '19 at 20:06
  • How many increments are you talking about?
    – Hot Licks
    Dec 23 '19 at 21:06
  • What is the context of the question? We are just speculating without it.
    – JeremyC
    Dec 23 '19 at 22:36
  • @EdwinAshworth Isn't it already plural? :) Tom plus-oned Dick yesterday, so it's no surprise if Dick plus-ones Harry today. Tom and Dick plus-one folks all the time, but Harry isn't plus-oning them back no matter how much they beg him to. it's completely regular! So the singular is he/she/it plus-ones, the plural is we/you/they plus-one, the past and past participle are both plus-oned, and the gerund/participle is plus-oning.
    – tchrist
    Dec 23 '19 at 22:51