Now, here is the conundrum. .9 repeating is EQUAL TO ONE. Not CLOSE to one, mind you, but EQUAL to one.

Nonsense, you reply. It is obviously less than one. Not by much – by an infinitely small amount, in fact. But the simple fact that it is not one is enough to demonstrate that it can’t be equal to one. It’s as close as you can get to one without being one.

Wrong! It is in fact equal to one, and that fact can be demonstrated mathematically in several ways.

via .9999999… is equal to 1.000000 « Mr. Barlow’s Blog.