Abs Returns the absolute value of a specified number. Abs(-1) 1M
Acos Returns the angle whose cosine is the specified number. Acos(1)0d
Asin Returns the angle whose sine is the specified number. Asin(0) 0d
Atan Returns the angle whose tangent is the specified number. Atan(0) 0d
Ceiling Returns the smallest integer greater than or equal to the specified number. Ceiling(1.5) 2d
Cos Returns the cosine of the specified angle. Cos(0) 1d
Exp Returns e raised to the specified power. Exp(0) 1d
Floor Returns the largest integer less than or equal to the specified number. Floor(1.5) 1d
IEEERemainder Returns the remainder resulting from the division of a specified number by another specified number. IEEERemainder(3, 2) -1d
Log Returns the logarithm of a specified number. Log(1, 10) 0d
Log10 Returns the base 10 logarithm of a specified number. Log10(1) 0d
Max Returns the larger of two specified numbers. Max(1, 2) 2
Min Returns the smaller of two numbers. Min(1, 2) 1
Pow Returns a specified number raised to the specified power. Pow(3, 2) 9d
Round Rounds a value to the nearest integer or specified number of decimal places. The mid number behaviour can be changed by using EvaluateOption
.RoundAwayFromZero during construction of the Expression object.
 Round(3.222, 2) 3.22d
Sign Returns a value indicating the sign of a number. Sign(-10) -1
Sin Returns the sine of the specified angle. Sin(0) 0d
Sqrt Returns the square root of a specified number. Sqrt(4) 2d
Tan Returns the tangent of the specified angle. Tan(0) 0d
Truncate Calculates the integral part of a number. Truncate(1.7)1

It also includes other general purpose ones.

in Returns whether an element is in a set of values. in(1 + 1, 1, 2, 3) true
if Returns a value based on a condition. if(3 % 2 = 1, true, false) true
Contains Returns true if the first string contains the second. Contains(‘1234′, ’23’) true
Match Indicates whether the specified regular expression (second argument) finds a match in the specified input string (first argument). Match(‘1298-673-4192’, ‘^[a-zA-Z0-9]\d{2}[a-zA-Z0-9](-\d{3}){2}[A-Za-z0-9]$’) true
ContainsUser Indicates whether the specified list of users and groups (first argument) contains specified user (second argument). ContainsUser([People], [CurrentUserLogin]) whether ‘People’ field contains the current user
 Indicates whether the specified list of users and groups contains the current user. ContainsCurrentUser
 whether ‘People’ field contains the current user
 Indicates whether the specified user has a specified set of permissions on the current item. DoesUserHave
(CurrentUserLogin, ‘Contribute’)
 whether the current user has ‘Contribute’ permissions on the current item.
 Indicates whether the current user belongs to the specific SharePoint group. IsCurrentUser
 whether the current user belongs to ‘Members’ group.