DMcG

1 is exactly the same number, mathematically speaking, as 0.9999999999 recurring.

I know, but in the context of this thread which has a range of countributors from MtheGM who describes himself as "entirely unmathematical" to people such as Airymouse and your good self who are clearly highly mathematiccally educated (I'm somewhere inbetween) I think it has a certain "Well I never" factor.

I have seen a proof of 1 = 0.999 recurring but can't remember it. Do you have it to hand?