how to compute the average values of a row in table

[TML]

help i want to compute the value of my table\[code\]<input type="hidden" name="stud_no[]" value="http://stackoverflow.com/questions/15781727/<?php echo $row['student_no'];?>"><input type="text" name="prelim[]" value="http://stackoverflow.com/questions/15781727/<?php echo $row['prelim_pts']?>"></td><td><input type="text" name="midterm[]" value="http://stackoverflow.com/questions/15781727/<?php echo $row['midterm_pts']?>"></td><td> <input type="text" name="final[]" value="http://stackoverflow.com/questions/15781727/<?php echo $row['finals_pts']?>"></td><td><?php echo $row['average_pts']?></td>\[/code\]