You probably use VLOOKUP() function to find exact matches in Microsoft Excel, but you can also find the closest value when you don't know the exact value.

Combine INDEX and MATCH: Use MATCH to find the row or column number and INDEX to retrieve the value at that position.

There's one trick, though, that separates the quants from the interns. That trick is Index/Match, a function that can find any value in any spreadsheet.

Prevent duplicates before they happen by combining a simple function with data validation.