Condition based replacements of Cells with other values

A quicker alternative might be:

Sub Example()
    Dim rngArea As Range
    For Each rngArea In Selection.Areas
        With rngArea
            .Value = .Parent.Evaluate("IF(ISNUMBER(" & .Address & "),1+5-" & .Address & ",REPT(" & .Address & ",1))")
        End With
    Next rngArea
End Sub