Calculating between sheets.

Hi all.

I need to add amounts between sheets within the 1 workbook. I want to do this in a simplistic way so that the user can decide on the amount to be transfered and where the amount is transfered to.

For example in the workbook attached sheet 1 has an opening balance of £148,500 (cell C4).

If the user wanted to take £20,000 of that opening balance and trasfer it to the opening balance of sheet 2 in the cell C4 I'd like them to enter a figure in the cell that they want to transfer into. (See cell D27).

I think I have the bones of it yet want to add a formula into the range D27:D32 that will allow whatever the figure added is in that range is automatically taken away from cell C4 and is added into cell C4 into the corresponding sheet selceted.

Please help thanks.