Hi Epinn,

Great to hear that you are learning about the F9 function key in Excel. It can definitely come in handy when troubleshooting formulas.

To answer your question, unfortunately, there is no shortcut key to reverse the F9 calculation. Once you press F9 and replace a portion of the formula with a calculated value, it is replaced permanently. However, you can undo the calculation by pressing Ctrl+Z immediately after pressing F9. This will undo the calculation and revert the formula back to its original state.

If you have already pressed Enter after pressing F9, then the only way to get back to the original formula is to either manually retype it or copy and paste it from a backup copy of the worksheet.

Regarding your research on compiling complex worksheets, the rule you mentioned is a good one to follow. By placing primary calculations at the top and left of the worksheet, you can ensure that they are calculated first and that any subsequent calculations are based on accurate values. This can help prevent errors and improve the overall performance of your worksheet.

1. Press F9 to replace a portion of the formula with a calculated value.
2. Press Ctrl+Z immediately after pressing F9 to undo the calculation and revert the formula back to its original state.
3. Manually retype the formula or copy and paste it from a backup copy of the worksheet if you have already pressed Enter after pressing F9.
4. Place primary calculations at the top and left of the worksheet to ensure accurate values and improve performance.