When pasting code, please use code tags. Click the # icon to insert them.
I corrected some typos.
Sub CheckSum()
Dim Answer As Integer
Dim rOne As Range, rTwo As Range
Dim sOne As Double, sTwo As Variant
Set rOne = Sheets("tblOne").Range("F1:F9")
Set rTwo = Sheets("tblOne").Range("E15:E51")
sOne = Application.WorksheetFunction.Sum(rOne)
sTwo = Application.WorksheetFunction.Sum(rTwo)
If sOne <> 1 Or sTwo <> 1 Then
Answer = MsgBox("***", vbCritical + vbYesNo, "***")
If Answer = vbYes Then
Exit Sub
ElseIf Answer = vbNo Then
Worksheets("tblTwo").Select
End If
ElseIf sOne = 1 And sTwo = 1 Then
Worksheets("twlTwo").Select
End If
End Sub