35. Excel has a bunch of little shortcuts to make your life easier.
If you press (Fn + ) F4 while you’ve got a formula selected, it will cycle through absolute references. (Absolute references are things that don’t change when you fill a cell column; if you drag a cell with A1 in the formula to the right, that will become B1, then C1, etc., but if you drag a cell with $A$1 to the right, it will stay $A$1 in every cell.) It goes, I believe, from A1 to $A$1 (fixed in both directions) to $A1 (fixed column; changing row) to A$1 (fixed row; changing column) and then back to A1 with each push of a button.
And ALT-F4 will attempt to close your worksheet, so don’t listen to whatever asshole decides to recommend that in the comments.
