Multiplication expression based on value in one field

[eddykwan_]

Hi Everyone,

I have multiplication condition with my expectation is :

1. Calculate in one field and sequantially

2. Value 1 * 2 = 2 (Column 2)

     Value 2 * 2 = 4 (Column 3)

     Value 4 * 2 = 8 (Column 4)

Please help how to write this Expression Calculation?

Thank you

[Mark_Little]

Can you expand you example of explanation?

As from what i can make out you are just doing an expression of 

Calc * 2

[eddykwan_]

I want the result value is sequentially in same field.

I can't use Above function because this function need value from other field.

My expectation is I want calculate the value like Above function but in the same field only.