Lets say I have 3 columns.
I want to deduct from cell C1 when # is put in cell A1 and zero out A1 after
the calculation.
Also I want to add to cell C1 when # is put in cell B1 and zero out B1 after
the calculation.

you can accomplished that using vba.

Go to TOOLSMACROVisual Basic Editor

then click on the sheet and paste this code in the code area.

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Cells(1, 3).Value = Cells(1, 3).Value + Cells(1, 1).Value
Cells(1, 3).Value = Cells(1, 3).Value - Cells(1, 2).Value
Cells(1, 1).Value = 0
Cells(1, 2).Value = 0
End Sub

'-----------------------------------------------------------------
Private Sub Worksheet_Change(ByVal Target As Range)
'-----------------------------------------------------------------
Const WS_RANGE As String = "A1:B1"

On Error GoTo ws_exit:
Application.EnableEvents = False
If Not Intersect(Target, Me.Range(WS_RANGE)) Is Nothing Then
With Target
Select Case .Address
Case "$A$1"
.Offset(0, 2).Value = .Offset(0, 2).Value - .Value
Case "$B$1"
.Offset(0, 1).Value = .Offset(0, 1).Value + .Value
End Select
.Value = 0
End With
End If

ws_exit:
Application.EnableEvents = True
End Sub

'This is worksheet event code, which means that it needs to be
'placed in the appropriate worksheet code module, not a standard
'code module. To do this, right-click on the sheet tab, select
'the View Code option from the menu, and paste the code in.





--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)

"chris1bcoo" wrote in message
...
Let's say I have 3 columns.
I want to deduct from cell C1 when # is put in cell A1 and zero out A1
after
the calculation.
Also I want to add to cell C1 when # is put in cell B1 and zero out B1
after
the calculation.

Re your private email, you need to adjust the cell references to your data

'-----------------------------------------------------------------
Private Sub Worksheet_Change(ByVal Target As Range)
'-----------------------------------------------------------------
Const WS_RANGE As String = "A2,D2"

On Error GoTo ws_exit:
Application.EnableEvents = False
If Not Intersect(Target, Me.Range(WS_RANGE)) Is Nothing Then
With Target
Select Case .Address
Case "$A$2"
.Offset(0, 2).Value = .Offset(0, 2).Value - .Value
Case "$D$2"
.Offset(0, -1).Value = .Offset(0, -1).Value + .Value
End Select
.Value = 0
End With
End If

ws_exit:
Application.EnableEvents = True
End Sub

--
HTH

Bob Phillips

(remove xxx from email address if mailing direct)

"Bob Phillips" wrote in message
...
'-----------------------------------------------------------------
Private Sub Worksheet_Change(ByVal Target As Range)
'-----------------------------------------------------------------
Const WS_RANGE As String = "A1:B1"

On Error GoTo ws_exit:
Application.EnableEvents = False
If Not Intersect(Target, Me.Range(WS_RANGE)) Is Nothing Then
With Target
Select Case .Address
Case "$A$1"
.Offset(0, 2).Value = .Offset(0, 2).Value - .Value
Case "$B$1"
.Offset(0, 1).Value = .Offset(0, 1).Value + .Value
End Select
.Value = 0
End With
End If

ws_exit:
Application.EnableEvents = True
End Sub

'This is worksheet event code, which means that it needs to be
'placed in the appropriate worksheet code module, not a standard
'code module. To do this, right-click on the sheet tab, select
'the View Code option from the menu, and paste the code in.





--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)

"chris1bcoo" wrote in message
...
Let's say I have 3 columns.
I want to deduct from cell C1 when # is put in cell A1 and zero out A1
after
the calculation.
Also I want to add to cell C1 when # is put in cell B1 and zero out B1
after
the calculation.