Decrease Evenly

I've been working on the Meringue Yoke Cardigan from Interweave Knits and I finally reached the yoke decreases only to find that the pattern stated simply decrease x number of stitches evenly. Whahaaa?! That's annoying. I like the pattern tell me how to make the sweater. Like it's supposed to. Not, "here do some math." So I tried to divide the decreases by the number of stitches but that number is not accurate since each decrease takes two stiches and I want one at each edge. I found I would reach the end of the rows with either not enough decreases or too many to fit on the row. Very irksome.

I thought long and hard about this problem and decided to search the internet because it is all knowing, well sort of. Someone else must have encountered this same problem before and come up with a viable solution and it's likely that they posted it.

The first thing I came across was from the author of the pattern and involved doing long division by hand. To me it didn't look mathematically plausible and anything that involves arithmetic without a calculator is just silly, so I kept looking.

I then came upon this lady's page! She uses real math! SCIENCE! EQUATIONS! They're great. I tried this formula and it worked. Simple, easy, calculator friendly. Maybe I should send it to the pattern author. :)