0.999...

The repeatin decimal continues wi an infinite nummer o nines.

In mathematics, the repeatin decimal 0.999... (sometimes written wi mair or fewer 9s afore the final ellipsis, or as 0.9, 0.(9), or $\scriptstyle \mathbf {0} .\mathbf {\dot {9}}$) denotes a real nummer that can be shawn tae be the nummer ane. In ither wirds, the seembols "0.999..." an "1" represent the same nummer. Pruifs o this equality hae been formulatit wi varying degrees o mathematical rigor, takin intae accoont preferred development o the real nummers, backgrund assumptions, historical context, an target audience.