A data table is a range of cells in which you can change values in some of the cells and come up with different answers to a problem. A good example of a data table employs the PMT function with different loan amounts and interest rates to calculate the affordable amount on a home mortgage loan.
It is basically used for making emi list for many items etc...
steps to apply data table :
1. select the cell with the total data on which you want to apply the same formula.
2. Click on "Data Tab" --- "What if.. Analysis" -- Data Table.
3. Select the cell as desired.
4. Click on OK.