Comment Comment by 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. parent Macha 4 years ago
"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.