sub quantity automatically from outcome factor and add quantity manually(just one column)

hi to all

there is a serous problem. i have a quantity column in my bank. i want to update it by another quantity column in outcomefactor and manually with hand!
in quantity from outcomefactor, my quantity in bank must be updated with subbing.
in other case i must be able to add (raise) quantity cells in bank.

so:
1- i have an original quantity in bank and other quantity in outcome factor.

2- auto subbing update in bank by outcomefactor(with vb code). if i change quantity in outcomefactor the numbers must be computed from first place(i must not loss base numbers until the table in outcomefactor is not completed or excel is not closed)

3- manually adding update in bank by hand(just manually with hand).

4- original table is in bank and other table is in outcomefactor.

5- i want the values from outcomefactor to be subtracted from the values in bank.

6- the base values in bank must not be deleted. because it is possible that i need to change any value in the outcomefactor, until i close excel or complete the outcome factor. (bank is main table for doing my job)

7- for doing this things automatically i need VB code(a macro). because vb code does not fill the cell and in future i can add to bank values by hand(manually).

8- i need a vb code for auto reduce and store previous data. and it be possible to raise the data by hand without any error or problem.

please help me
thanks

Not sure I understand your request

Are you saing you want the values from Outcome to be subtracted FROM the values in Bank? Or is it the values from Bank to be subtracted from Outcome?

Also, keep in mind, that a cell can contain either a value or a formula, not both, so if you have a formula in a cell, and you manually enter a value in that same cell, the formula is now lost.

Perhaps you could provide a few samples showing step by step how you would do this by hand?