Multiplying values in Excel 2010 (Same cell)
If you can spare 1 cell somewhere else in the worksheet/book, you can type 1.333 in that cell, copy that cell and then select A1, "Paste Special" > "Multiply".
This works for multiple selections to multiply :)
After that, delete the cell containing 1.333.
The below VBA macro appears to work:
Public Sub Convert()
Dim Cell As Range
For Each Cell In Selection
If Not IsError(Cell) Then Cell = Cell *1.333
Next Cell
End Sub