How do I put wrapper code around the below, so that I can select a
range of "many" cells and have the code execute on each cell in turn?

For each cell in selected range (selection) . . .

Sub Adjust_Formula()
ActiveCell.Formula = "=" & ActiveCell.Value * 2 & "*(QTR/4)"
End Sub

The formula works fine on a single cell.

Many thanks,

Fred Holmes