I have a 2003 spreadsheet that lists these column headers

LastName Firstname Grade NumberOfTardies

Each student has a row for each quarter, regardless of the number of
tardies the student received. So, Billy Thompson's would look like
this:

LastName Firstname Grade NumberOfTardies
Thompson Billy 8 0
Thompson Billy 8 1
Thompson Billy 8 8
Thompson Billy 8 7

What I want to do is have it total up the number of tardies per kid
per year, so in my example it would take all those totals and
ultimately look like this:

LastName Firstname Grade NumberOfTardies
Thompson Billy 8 16

Anyone know an easy way of doing that?