Most formulae used in Excel spreadsheets contain references to other cells or ranges of cells. There are three types of references that can be used: Relative, Absolute or Mixed.
Relative: Both the row and column references are free to change when the formula is copied to another cell. Example: =A1
Absolute: Both the row and column references are fixed and do not change when the formula is copied to another cell. Example: =$A$1. (Note the dollar symbol $ before both the column and row labels)
Mixed: Either the row or column reference is fixed and does not change when the formula is copied to another cell. Example of fixed column: =$A1, Example of fixed row: =A$1. (note the positioning of the dollor symbol $ in both cases)
Please see our brief guide to Absolute and Relative references
