String and Value workbook reference

Jim

For both examples in your first post just replace the values with the appropriate references.

And Cells(1, i) <> Sheets("Sheet1").Range("A1").Value  _

ActiveCell.FormulaR1C1 = "=RC[-2]-" & Sheets("Sheet1").Range("B1").Value

' or

ActiveCell.FormulaR1C1 = "=RC[-2]-Sheet1!R1C2"