"Subscript out of range" error

Hello , below is my function. But my code throws error at "For Each " line as shown below

Public Function displayExpectedValues()
startRowValue = InputBox("Enter FirstRow Number to read data")
EndRowValue = InputBox("Enter Last Row Number to read Data")

For Each c In Sheets("Reasult Reader").Range("Q17:Q70") ' SubScript out of range error , thrown at this line.
    c.Offset(0, 2) = c.Offset(0, 1).Value + c.Offset(0, 3).Value
    startRowValue = startRowValue + 1
    If startRowValue = EndRowValue Then
          Exit For
    End If
Next c
End Function

Can you please help me to remove this error ?

Eventhough i changed the function as given below , still the same error at shown line

Public Function displayExpectedValues()
startRowValue = InputBox("Enter FirstRow Number to read data")
EndRowValue = InputBox("Enter Last Row Number to read Data")

c = Sheets("Reasult Reader").Range("Q17") ' SubScript out of range error , thrown at this line.

Do While startRowValue < EndRowValue
    c.Offset(0, 2) = c.Offset(0, 1).Value + c.Offset(0, 3).Value
    startRowValue = startRowValue + 1
Loop
End Function

Thank you very much.