I'd like to ask some questions: 1) What are the OPs? 2) I've seen written the call to get the square of a number, but how can I get it working with negative numbers? 3) What's the call to input a number, like the Zreduce input? _______________________________________________ Filipe Pinto homepage - www.geocities.com/SiliconValley/Park/4098/ email - filipepinto@mail.telepac.pt