I used to play formula roulette every time I dragged the fill handle, hoping Excel wouldn't misinterpret my intentions. Was I supposed to lock the column, the row, or both? Then, the dollar signs ...

Don't panic—your Excel isn't broken. If your column letters suddenly turn into numbers, you've stumbled into R1C1 mode. While it looks like a glitch, it's actually a high-level tool that lets you ...