Dear guys..

I have some problem..
It's about creating tables with the default value in some fields.
for instances...

<mytables.dbf>
field
- A
- B 
- C (Intend Value = A + B)
- D (Intend Value = A * B)

How to make that happen in field validation or else
cause i want when i append record
i want when we input value in A, and B automatically C and D processed


could any of you help me...

thx