Update the value of specific column using the values of other columns on-the-fly.

[Hongyi Zhao]

I want to edit a table with 5 columns, where the first column is
calculated from the other columns as below:

val_col1 = 20% * val_col2 + 30% * val_col3 + 40% * val_col4 + 10% * val_col5

I want to let emacs update the column 1, i.e., the weighted mean
result of other columns automatically and on the fly when I input the
values for other columns.

Is this possible with emacs? Any hints will be highly appreciated.

Regards
-- 
Assoc. Prof. Hongyi Zhao <hongyi.zhao@gmail.com>
Theory and Simulation of Materials
Hebei Polytechnic University of Science and Technology engineering
NO. 552 North Gangtie Road, Xingtai, China