Replace the following lines: 5: ` Using calc = System.Math;` 13: `double i = calc.Round(d, 2);`...

Ok, I admit I'm confused by the previous answers and would love to know the right answer, if there is any(!!) I'm not a C# guy but from what I recall from the time when Borland had the world's best c++ compiler (ya I know, I'm getting old....) I lear...