Question

There is a rounding error using the decimal because it reads another datatype from another system. So I was wondering if it is possible to overload the + operator on the decimal type? All the examples I see is on new defined structs.

Answer 1

No decimal is a value type and as such cannot be inherited. You would have to correct the rounding outside of this, perhaps via an extension method e.g.

public static decimal Add(this decimal value, ...)
{
    ... do manual calculation & rounding
}