==GAMMA(number)
        The gamma function is used to calculate the gamma value of a real number. The Sourcetable function GAMMA(2.5) returns the gamma value of 2.5, which is 1.329.
The Sourcetable function GAMMA(-3.75) returns the gamma value of -3.75, which is 0.268.
The Sourcetable function GAMMA(-2) returns 0 because a negative integer is not a valid argument for the gamma function.
The GAMMA function is a mathematical tool used to calculate the gamma function value of a given number.