حرب ان تضع هذا الكود في حدث الصفحة
Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Column <> 1 or Target.Row > 100 Or Target.Count > 1 Then GoTo 1
If Not (IsNumeric(Range("e37"))) Or Not (IsNumeric(Target)) Then GoTo 1
Application.EnableEvents = False
Myval = Target.Value
Target.Value = [e37] - Myval
1:
Application.EnableEvents = True
End Sub