As a general rule, most woodworkers really hate math. For instance, the type of math I'm referring to is when they need to calculate the distance that half a dozen boards of varying widths will add up to when the boards are glued up. 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.