The annuity function is used to compute the present or future value of an ordinary annuity. Rate is the interest rate per period, and periods is the number of periods over which the value is calculated. The formula for annuity is: annuity (rate, periods) = (1 - (1+rate) periods) / rate The annuity function is more accurate than computing the formula above using basic arithmetic operations and exponentiation, especially when rate is small.

The ln function returns the base-e (natural) logarithm of the number passed to it.

The ln1 function returns the base-e (natural) logarithm of the sum of 1 plus the number passed to it. That is, it computes ln(1+number). If number is small, the result is more accurate than using standard arithmetic operations.

The log2 function returns the base-2 logarithm of the number passed to it.

The max function returns the highest-value number from a list of numbers passed to it. If the source of the list is a container with more than one line in it, only the first line is used.

The trunc function returns the integer part of the number passed to it. Any fractional part is desregarded, regardless of sign.