I'm fairly proficient at math yet the 'duh' moments that are the worst all involve my inability to measure and figure correctly. I once was sashing the sides of a panel and wanted fussy-cut pieces placed across from each other in the sashing. One side went on fine. The other used up all my remaining fabric as I continued to re-cut one piece to match. Maybe I should say that my 'duh' moments mostly involve panels, as I just can't seem to measure and calculate correctly in spite of my ability to know exactly what to do. My example is not my only panel caper.