Practical
Validate functions and formulas
Prove one formula before safely extending it across the range.
Write the condition in plain language
State what should be returned under each condition before nesting functions.
Separate moving and fixed references
Identify which cells must move and which ranges stay fixed before choosing reference type.
40 items · 40 min40 minutesFloors + 70
Test boundary cases
Check values just below and above a condition, blanks, errors and ties.
Fill only after validation
Confirm the first result and references, then copy and inspect the first and last cells.