Forgetting the meaning of the term: "Whole Number" seems common in the answers, and in the Question.
Getting the whole number from the number: 4 is simple:
1 x 4 = 4 <- A Whole Number! The first Whole Number!
2 x 4 = 8 <- A Whole Number!
3 x 4 = 12 <- A Whole Number!
Rounding a Number, to get a Whole Number is a cheats method of getting the Whole Numbers! Rounding it removing the Non-Whole Number part of the Number!
1.3 x 4 = 5.2 <- NOT a Whole Number!
1 x 343564564.4342 <- NOT a Whole Number!
Its important to understand what a Whole Number is!
4 / 1 = 4 <- A Whole Number!
4 / 2 = 2 <- A Whole Number!
4 / 3 = 1.333 recurring <- NOT A Whole Number!
Please ask, and answer the questions with a bit more Accuracy Peeps...
double A = Math.Abs(343564564.4342);
double B = Math.Floor(343564564.4342);
double C = Math.Ceiling(343564564.4342);
double D = Math.Truncate(343564564.4342);
Returns:
A = 343564564.4342
B = 343564564
C = 343564565
D = 343564564
or:
double E = Math.Round(343564564.4342, 0);
E = 343564564
Is a Mathematical Function, thus changing the Number, and not working with Whole Numbers. Your Rounding Non-Whole Numbers!