How to round System.Decimal in .Net to a number of significant figures

Question

I have a System.Decimal number

0.00123456789

and I wish to round to 3 significant figures. I expect

0.00123

with the behaviour to be a roundi

Answer 1

in example:

decimal a = 1.9999M;
decimal b = Math.Round(a, 2); //returns 2