Yes, I've seen and skimmed this document, but, not to be rude, but I'm not interested in becoming a computer scientist in order to write a script to do basic math. Adding together 0.001 40 times is pretty basic and if my calculator can do it, I not sure I understand why Perl won't.
Now you say you're studying chemical diffusion so I assume you would have heard of significant figures? Surely your professor, when discussing significant figures, would have explained the basic limitations of adding machines (calculators/computers)?
I was hoping, after reading that document, you would ask explicitly how to round numbers for display purposes in perl.
While you can create a calculator using perl (like Tk::Calculator::RPN::HP ), and expect it to do rounding like your pocket calculator, perl itself, not being a calculator, won't hide the details of floating point arithmetic from you, so it is good knowledge to have.
Any scientist using computers for calculations needs to know the limits of his tools.