title: Append a sumproduct at the end of an existing formula for each cell
body: <p>SUPPOSE cell G1 in my worksheet has this formula 
  =$R$5*I4+$S$5*H4+$T$5*G4+$U$5*F4+$V$5*E4+$W$5*D4+$X$5*C4+$Y$5*B4</p>
  
  <p>G2 has a existing different formula
  =$R$5*I4+$S$5*H4+$T$5*G4+$U$5*F4</p>
  
  <p>now to this existing formula i want to add a new sum product $X$5*A4
  to make the new formula of G1 like this</p>
  
  <p>=$R$5*I4+$S$5*H4+$T$5*G4+$U$5*F4+$V$5*E4+$W$5*D4+$X$5*C4+$Y$5*B4+<strong>$X$5*A4</strong></p>
  
  <p>and that of G2 like this
  =$R$5*I4+$S$5*H4+$T$5*G4+$U$5*F4+<strong>$X$5*A5</strong></p>
  
  <p>the initial formula in all the cells is different, so that's why i am thinking of writing a macro. Please help me</p>
  
  <p>I have made this code looking at the comments:</p>
  
  <pre><code>        Sub test2()
  
          Dim myRange As Range, Cell As Range
          Dim targetsheet As Worksheet
          Set targetsheet = Worksheets("Sheet1")
          Dim abc As String
  
  
          For i = 1 To 14
           abc = "R7" &amp; "C" &amp; (i + 24)
              With targetsheet
              Set myRange = .Range(.Cells(77, i + 2), .Cells(87, i + 15))
              End With
          '    MsgBox myRange
              For Each Cell In myRange
                  If IsEmpty(Cell) Then
                  'MsgBox ("=" &amp; abc &amp; "*R[-75]C[" &amp; (-i + 1) &amp; "]")
  
                      Cell.FormulaR1C1 = "=" &amp; abc &amp; "*R[-75]C[" &amp; (-i + 1) &amp; 
                         "]"
                  Else
                      Cell = Cell.FormulaR1C1 &amp; "+" &amp; abc &amp; "]*R[-75]C[" &amp; (-i 
                    + 1) &amp; "]"
                  End If
              Next Cell
          Next i
  
          End Sub
  </code></pre>
  
  <p>now, this code is working well for i =1 but as soon as i turns 2 ; 
  the value of Cell.FormulaR1C1 becomes <strong>R7C25*R[-75]C</strong> please help me correct this. THANKS</p>