Sub ClasserDates()
Dim dercol%, i%, j%
Application.ScreenUpdating = False
With Sheets("T1")
dercol = 5 + 4 * Application.Count(.Rows(3))
For i = 6 To dercol Step 4
For j = i + 4 To dercol Step 4
If .Cells(3, j) < .Cells(3, i) Then .Columns(j).Resize(, 4).Cut: .Columns(i).Insert
Next j, i
For i = 6 To dercol Step 4: .Cells(1, i) = 1 + (i - 6) / 4: Next 'numéros en 1ère ligne
End With
End Sub