What is the biggest number you can round to 110000?

Answer 1

There is no biggest number that rounds to 110000. There is a smallest number that rounds higher. 110000.5, also represented by 110000.4999(infinitely repeating 9s) is the smallest number that rounds up to 110001.

110000.49 works, so does 110000.499, so does 110000.49999, so does 110000.4 followed by any FINITE string of 9s. But 110000.4 followed by an infinite string of 9s does not.

The reason there is no biggest number that works is that if you were to pick ANY number that works, I could simply go one decimal position further.

The numbers that round to 110000 form the half-open interval [109999.5,110000.5)