In the regexp I'd just look for

• an arbitrarily long string of zeroes and chop them off starting with the first one and
• an arbitrarily long strong of nines and chop them off starting with the first one, then add one to the end of the remaining number to make it round up.

By handling rounding in both directions you save yourself some trouble later on.

You didn't say, was it necessary to retain the tiny amount that you adjusted by? My suggestion doesn't keep that information -- I assumed it was irrelevant.

--t. alex

"Mud, mud, glorious mud. Nothing quite like it for cooling the blood!"
--Michael Flanders and Donald Swann