Exam 77-420 Microsoft Excel 2013 4. Apply Formulas and Functions 4.1 Apply Cell Ranges and References In Formulas and Functions: Reference Cell Ranges in Formulas	Cell References When you created the sales spreadsheet, you selected a range of cells to AutoFill. If we put 100 for the quantity in the first cell and 105 in the next, Excel fills down the series and adds 5 more to each cell.  If you wanted a different forecast you could enter new quantities in the first and second cells and use the AutoFill again. This could get old very fast. It is also a rather inflexible method of changing the data. There is a better method: reference cells.Reference cells set up one place to enter the data. All of the other equations and spreadsheets that depend on that data look it up in the reference cells.