[wbercx]

How would you interpret “+/- 10 years”?

[Macha]

As a margin of error.

"this tree was planted 200 years ago, +/- 10 years" -> the tree was planted between 190 and 210 years ago.

"this comet will next be seen in 100 years, +/- 10" -> The comet will visible between 90 and 110 years from now.

[wbercx]

Yeah, interesting. In The Netherlands it is commonly used to mean "more or less", or "approximately", unless it is used in formulas.

[davidbanham]

For “approximately 10 years” I would note it as ~10. Native Australian English speaker.

[ben174]

In English, "give or take".

[simonh]

+10 years could be interpreted as 10 years in the future, and makes perfect sense in that context, but -10 years for the past seems weird. I'm not sure why.

[wingerlang]

I don’t think they are comparable really.

10+ years means over ten years.

+/- 10 years is an addition/subtraction and making a range.