Adding fields in duplicate records

Hi Group,

I am getting duplicate records in Internal table , my requirement is to add field values of the duplicate records.

for example:

Emp ID               division                      Marks          

900                      01                               60

900                      01                               40

900                      01                               20

Output should be

-------------------------

900                     01                                  120

Can any body please suggest how to do it in ABAP.