When editing an Excel file with multiple formulas, it is sometimes useful to switch between Excel's normal display, which shows the results of the formulas in the spreadsheet, and a display mode that shows the actual formulas in the cells. The normal method to do this would be:
open the File menu
go to Options, then Advanced
scroll down to Display Options for this Worksheet
check the box next to "Show formulas in cells instead of their calculated results," and uncheck the box to display results again.
However, there is also a convenient keyboard shortcut that does this much more quickly. The keystroke is Ctrl-~; press it once, and Excel displays formulas instead of results. Press it again, and the results appear again. As a bonus, when you use this tip to display formulas in cells, select a cell with a formula, and Excel outlines the cells that are referenced in the formula.