Hi, I'm quite new to Mathematica, and I've been trying to use it to solve some PDE's numerically, and I eventually end up with a really large matrix I have to find the solution for. I was think the calculation would go by faster if I could take the precision of the numbers down. I think its using double and I want it to be floating pt numbers. I guess by precision I mean the number of digits, after the decimal point. So maybe I mean to say accuracy. In any case, is there a way that I can tell mathematica to only use lets say 5 digits after the decimal point? I've already read some of the documentation, about using $MaxPrecision, and WorkingPrecision, but it doesn't seem like there is a global way to set the precision. Is there? Can I just say "I want precision 5" somehow and set that for the whole notebook? Thanks in advanced.