Sometimes it is hard to understand the logic of complex Excel formulas – Especially when there are lots of references to different cells or ranges. Excel has (of course 🙂 ) great helper tools for this. There is set of Audit Formulas -tools in Ribbon bar’s Formulas tab.
Trace Precedents: Shows with arrows from where the selected formula takes it’s parameters
Trace Dependents: Shows with arrows the formulas that contains reference to the selected cell
Check for Errors: Tool for analysing possible errors in formula
Following video demonstrates how to use Excel’s conditional formatting to highlight dates that are older than 70 days. The formula takes into account that empty cells won’t be highlighted. Following formula in D1’s Conditional Formatting does the trick: