LOL..your not dumb..this has always been an issue with me..I have designed and quilted for years..also teach some classes for a LQS ..personally ..mathematically..a 1/4 inch is a 1/4 inch..if someone wants me to do a scant..then they need to tell me to do 3/16 or something..lol..it still drives me crazy !! I know all the excuses they use for why they do it..but I find if u do exact 1/4 it works out fine !!