The following may assist a little bit but its not perfect... I know I have been there before.. its a bit of a long winded process I am afraid:
anyway from the help manual:
4.MAXV(expression1, expression2, ...)
Returns the maximum of the two or more expressions listed in the brackets. For example, MAXV(-2, 10, 5, 0) will return 10. The expressions can be numbers, arithmetic expressions, trigger and user variables etc.
5.MINV(expression1, expression2, ...)
Returns the minimum of the two or more expressions listed in the brackets. For example, MINV(-2, 10, 5, 0) will return -2.