Sum of the value from virtual column

[Celes]

hi,

Please help. I need to get the sum of the value from my virtual column but it returns the sum of all virtual column in my app : for example

ColumnName virtual column 1 i have 2, 3, 4 sum should be = 9

ColumnName virtual column 2 i have 4,5,6 sum should be = 15 but it returns 24 (because 9+15)

ColumnName virtual column 3 i have 7,8,9 sum should be = 24, but it returns the sum of all value from all the column which is 48.

this is my formula for sum column Sum([ColumnName ])

Any suggestion to improve my formula please