If you can think of evalf(123456) where 2 is the number of significant figures then 120000 is correct. BTW significant figures is something used a lot in Chemistry and Physics - more so in Chemistry. Quoting from a significant figures calculator Suppose we want
4 significant figures. We simply round the entire number to the nearest thousand, giving us
3,454,000 Sure in some ways it might sound nonsense but it depends on how it was used.
You could, if you wanted to, fashion you're own round function to work the way you want it to, just create a procedure for it. I use ceil, trunc, floor or evalf for most things. Actually, I don't believe I've ever used round.