As a general rule, most woodworkers really hate math, such as when it's necessary to calculate how boards of various widths will add up when they are glued up side to side. Or finding the metric or decimal equivalent to 19/32".
With that in mind, here is a handy conversion chart that you can download and print. Put this chart on a wall in your shop and you'll have the decimal (in inches) and metric (in millimeters) equivalents for fractional values of up to 1/64th of an inch.
It won't handle all of your math, but it certainly should help make some of your calculations a lot easier.