Somme avec variable en macro VBA

Sub somme()
Dim somme As Double
Dim ligne As Integer
Dim colonne As Integer
somme = 0
ligne = 2
colonne = 5

Do While Cells(ligne, colonne) <> ""
    somme = somme + Cells(ligne, colonne)
    ligne = ligne + 1
Loop

Cells(ligne, colonne) = somme

End Sub

Sub additionner()
Dim derlig As Long
derlig = Range("D65536").End(xlUp).Row
Cells(derlig + 1, 4) = Application.Sum(Range("D2:D" & derlig))
End Sub

Sub additionner()
Dim derlig As Long
Dim dercol As Long

derlig = Range("D3").End(xlUp).Row
dercol = Range("D2").End(xlToRight).Column

Cells(derlig + 1, 4) = Application.Sum(Range(Cells(2, 4), Cells(2, dercol)))

End Sub