GUIDE深度 · Deep dive
Excel Formula Basics
Excel formulas are about references and context: relative references change when filled, absolute references use $, and errors should be handled with IFERROR before complex functions.
References
A1 is relative; $A$1 is absolute; A$1 locks the row.
Whole columns like A:A are convenient but can be slow.
Errors and conditions
Handle #N/A, #DIV/0! and #VALUE! with IFERROR first.
Replace deep IF nesting with IFS or a lookup table.
FAQ
Why do results break after filling?
Relative references moved; add $ to lock them.
What if a formula gets too long?
Use helper columns or LET instead of one giant cell.