This is a modification of one of Bernie Deitrick's replies earlier this week
Copy the code below, right-click the sheet tab, select "View Code" and paste
the code into the
window that appears.
Change the
Set rngPCode = Range("D

")
to the column where the numbers will be entered.
This could be just a single cell as: Set rngPCode = Range("A2")
or a range as in: Set rngPCode = Range("B1:B10")
Also change: MyValue = 3.142 to reflect the value you want to add
Private Sub Worksheet_Change(ByVal Target As Range)
Dim rngPCode As Range
Dim MyValue As Double
MyValue = 3.142
Set rngPCode = Range("D

")
If Intersect(rngPCode, Target) Is Nothing Then Exit Sub
If Target.Cells.Count > 1 Then Exit Sub
On Error GoTo Reset
Application.EnableEvents = False
Target.Value = Target.Value + MyValue
Reset:
Application.EnableEvents = True
End Sub
best wishes