Calculating field

[florin]

How can I calculating value in a fields no1 and value1?
Initial, no1 and value1 is null.


name no value_in atr no1 value1
---------------------------------------------------
n1 4 20 in 4 20
n1 3 120 in 7 140 (7=4+3
and 140=120+20)
n1 2 out 5 100
(5=7-2 and 100=140-2*(140/7)
n1 2 30 in 7 130
(7=5+2 and 130=100+30)

 

[Guest]

Do you have some sequential field to sort by? Just trusting that the table
is in the right order might not be the best idea..

 

[florin]

Field Name is sort and I have another field Date who is sort.