Automatically Adding Values from Separate Columns in Excel

[Ray_Bloggs1258]

I have an Excel spreadsheet with 2 columns, A & B.  I would like column B to automatically populate a value once I insert a number into column A. 

Does anyone know how to do that?

For (column, row) (B, 2), I'm using the following simple formula:

=sum(B1-A2)

Eg: If B1 Value is 10, and I insert value of 2 into cell A2, then cell B2 would automatically populate the value of 12.

A    B

      10

2    12

Thanks,
Ray_Bloggs1258

[#2]

@Ray_Bloggs1258 

Enter the following formula in B2:

=IF(A2="", "", SUM(B1,A2))

Fill down a good way, for example to B1000.

The cells in column B will remain blank until a value is entered in the corresponding cell in column A.

[#3 · Accepted solution]

@Hans Vogelaar 

Thank you, Hans, that makes total sense and it worked perfectly.   

This is the first time I have ever tried "Blogging" and you answered the call quickly and correctly.

Very much appreciated.

- Ray (from Maryland)