This code works, but I'm having an issue with providing a value copy
of the FormulaR1C1 the another column in the same row. I've basically
indicated the line of code that is not working.

For Each myArea In myRng.Areas
myFormula = "=sum(r[-1]c:r[-" & myArea.Cells.Count & "]c)"
Set FormCell = myArea.Cells(myArea.Cells.Count).Offset(1,
0)
With FormCell
.FormulaR1C1 = myFormula
.Offset(0, 1).FormulaR1C1 = myFormula <- This is the
problem line, I want to put the value myFormula
' .Offset(0, 3).FormulaR1C1 = myFormula
End With
Next myArea