I have a table "normalisation.dbf" having fields 1. Regno 2.Appno 3. Name 4. dob 5. Boardcode 6. Maths 7. Physics 8. chemistry. The Boardcode field consists of 4types namely 1.Tamilnadu Board = 01 2. CBSE =02 3.Andhra Board = 03 4. kerala Board = 04.

I want to write normalisation code

Normalization procedure:
The marks obtained by the students in the relevant subject in the qualify examination conducted by the various boards hall be equalised with the marks obtained by the the students in the same subject in the qualifying examination conducted by the state board(i.e Tamilnadu board).

under the method of normalization in highest mark obtained by the student of various board in each subject shall be equated to the highest mark obtained by the student of the state board(i.e Tamilnadu board) in that subject and the relative marks of the other students in that subject shall be determined accordingly.

1. Tamilnadu Board
The highest mark in Maths is 200
The highest mark in physics is 200
The highest mark in chemistry is 200

2. CBSE board
The highest mark in Maths is 100
The highest mark in physics is 100
The highest mark in Chemistry is 100

3. Andhra board
The highest mark in Maths is 300
The highest mark in physics is 150
The highest mark in chemistry is 150

4. Kerala Board
The highest mark in Maths is 100
The highest mark in physics is 100
The highest mark in chemistry is 100

For example if the highest mark secured by a student of the stateboard (i.e Tamilnadu Bord) in Physics is 200 and the highest marks secured by a student of CBSE Board in same subject is 100, then both the highest marks will be considerd
to be equal to 200. if any other student of the CBSE board secure 70 marks in physics when the first mark in physics in the same board 100 then 70 marks secured by such student will be considered to equal to

(200*70)/100 = 140

can any one give How to write code for above question?