How Can I get the average value of cells

Hi There,

I generate a table with student name and grades for different courses. Now I want to auto calculate the average grade for all courses and show the result in the last Overall column. How can I do that.
Here is the column example:
Student| English | Math | Art | Music | Overall
Sam | A | B | C | D | average(A,B,C,D)

Question2:
Can I submit all the input values and store them into database?

Question3:
How can I dynamically load the column title not with the fixed text.