The System.Math class exposes several static methods that let you perform many common operations. These functions replace the VB6 functions with same name, but there are a few new functions that have no direct VB6 counterpart:

Ceiling(x) returns the integer equal or higher than the argument
Floor(x) returns the integer equal or lower than the argument
IEEERemainder(x, y) returns the remainder of the x/y division; it’s similar to the MOD operator, but it works correctly also with floating point numbers
Log10(x) returns the base 10 logarithm of the argument
Min(x,y) returns the lowest of the two arguments
Max(x,y) returns the hiighest of the two arguments
Atan2(x, y) returns the arc-tangent of x/y; it is similar to Atan, but it works correctly in all four quadrants
Sinh(x), Cosh(x), Tanh(x) return the hyperbolic sine, cosine, and tange of the argument

Console.WriteLine(Math.Ceiling(2.5))   ' displays 3Console.WriteLine(Math.Floor(-3.8))    ' displays -4

Finally, the Math class also exposes the E (Neper number) and PI constants.