Table calculations compute using the data on the screen rather than the data in the dataset.
The most commonly used table calculations are: Difference, % Difference, Rank, % Total, Running Total
You can modify the Table calculation to either look at the entire table of data on the screen, or only scan data within a specific pane at a time
Table calculations can go from basic to complex very quickly. The help topics listed above are for those who want to go beyond the common uses.