Google Sheets

#N/A can be a useful signal that a requested key has no match. Decide whether absence is expected before replacing the error with a blank or zero.

A division error can come from a real zero denominator or from missing input that a formula treats as zero. Those states should not automatically produce the same report value.

Dollar signs control which parts of a cell reference move when a formula is copied. They do not protect a cell from editing or keep its value confidential.

A circular dependency means a calculation eventually depends on its own result. Trace the loop before changing workbook settings or replacing the error with a fixed value.