How to add the values in several columns and give the result in another column of same row

Private Sub DataGridView1_CellValidated(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellValidated

        Dim cy As Integer

        'Get the current cell's Row
        cy = DataGridView1.CurrentCellAddress.Y   

        ' Add the first three columns (0,1,2) and display it in the 
        '  fourth column
        DataGridView1.Item(3, cy).Value = Val(DataGridView1.Item(0, cy).Value) + Val(DataGridView1.Item(1, cy).Value) + Val(DataGridView1.Item(2, cy).Value)

End Sub