0.999... = 1?

My stupid math prof tells me that .9999999... = 1. But I think he is just stupid.

So, what's your take?

Yes, .9 is equivalent to 1.

Look at it like this:

1/3 = .3
2/3 = .6

1/3 + 2/3 = .6

1/3 + 2/3 also equals 3/3, which is 1.