You just have to learn to tell the computer what arithmetic you would like done on certain rows and columns. Once this is set, it will work for the next group of students. Just change the names of students and save the document under a different name. No more pressing tiny calculator keys. No more angry students or parents who find silly mistakes in your math.
Computers can also easily figure percentages for tests and assignments with any number of problems.
Finally, this is a great help for those who have to keep budgets and want quick access to running totals.