I totally get it, beverages and dice mix well when sitting around a table with your buddies, but, could you clarify which math it is you're looking to have done for you?
Do you mean what you get to double/don't? or threat ranges and multipliers?
Range/multipliers mostly work out of box (some of the stuff in user-added content isn't perfect yet, and new stuff from LW sometimes has bugs, it happens, nobody's perfect), but when you need to adjust them manually (e.g. something net yet implemented quite right) you can use ShadowChemosh Adjustments; there are adjustments (per-weapon basis) for modifying both threatened range and crit multiplier
For what you get to double/not, the simplest rule of thumb is:
if it's extra dice (precision/sneak attack, elemental add, vital strike) you don't get to double it, if it's extra damage (devastating strike, strength damage, etc), you do
So, to crit:
take your multiplier * # of dice for your weapon, i.e. if 2d6 base, crit *3, grab 6 dice
take additional dice for +fire/acid/sneak attack/whatver
Roll all of that
Take the total "+" after your dice, multiply that * multiplier, and add that to your dice throw
For simpler multiplying, you can either use a calculator, a dice roller, or do it in your head; you likely only need to remember your multiplication tables from elementary school up to 9x3
i.e. +24 * 3 = (2 * 3 * 10) + (4 * 3) = 6*10 + 12 = 60+12 = +72
Write that down once on your whiteboard/scrap paper, and you never need to calc it again
