How can we add new field in the column contain Expression related to different fields?

Hi,

Below are sample table data in ssrs report,

ValueFor                  FirstHr    SecondHr    ThirdHr

Total Contacts                128      101         79

Abandons                       8       10           4

ValueFor,1Hrs,2Hrs and 3Hrs *are columns* Above,I need to add "Contacts Handled" filed under the "ValueFor" Column,its values depend on the same column in the different fields?

Contacts Handled=Total Contacts/Abandons

My Result is ,

      ValueFor                  FirstHr    SecondHr    ThirdHr

     Total Contacts                128      101         79

     Abandons                       8       10           84

    Contacts Handled               16      10.1       0.9415

How can i able to write Expression in FirstHr,SecondHr and ThirdHr columns?

please give any suggestions i need its urgent requirement.

please help me anyone?