I have looked around and can't seem to find anything. Something simple that would provide the number of days eleapsed between two date/times. This comes in handy for radioactive source decay calculations. Thanks, GL

Hello, I am very new to using Maple, so I must apologize for my ignorance in advance. I basically have 2 questions, 1) How do I force the use of a preferred unit that may not be the default for a particular unit system. For example, I prefer cm for length and keV for energy. I would like these to always be assumed by Maple. also 2) How can I use a unit that does not appear to be part of any unit system, such as "neutrons". I would like to enter values such as 1E8 [neutrons/cm^2] . . . etc. How does one do this in Maple. I appreciate your input. Best regards, GL Columbi