0.999.... = 1 (Why?) Sorry to put such a basic question on here, but it's not for homework so I figured I'd post here. On these forums, I've saw the issue of .99... = 1 brought up before; however, I recently discovered it in Math class. My teacher said it equals one because it is being rounded; however, it actually doesn't equal one. I understand what she means; however, for some reason, I recall seeing a formula that mathematically proved .99... = 1 without rounding. Perhaps I am seeing things.