While PowerShell itself comes with reasonably basic mathematical operators, the .NET class System.Math has a far wider variety.

The Round static method can be used to round up to a fixed number of decimal places. In the following example, the value is rounded to two decimal places:

[Math]::Round(2.123456789, 2) 

The Ceiling and Floor methods are used when performing whole-number rounding:

[Math]::Ceiling(2.1234)    # Returns 3 
[Math]::Floor(2.9876)      # Returns 2 

The Abs converts a positive or negative integer to a positive integer (multiplies by -1 if the value is negative):

[Math]::Abs(-45748) 

Numbers may be raised to a power:

[Math]::Pow(2, 8) # Returns 256 (28) 

A square root can be calculated:

[Math]::Sqrt(9)    # Returns 3 

The System.Math class contains static properties for mathematical constants:

[Math]::pi    # π, 3.14159265358979 
[Math]::e     # e, 2.71828182845905 

Methods are also available to work with log, tan, sin, cos, and so on.