Puedes hacer esto:
Dim rs1 As New ADODB.Recordset
Dim rstemp As New ADODB.Recordset
Dim monto as Double
monto=0
Set rstemp = Nothing
rstemp.Fields.Append "Num Operacion", adSingle
rstemp.Fields.Append "Monto", adDouble
rstemp.Fields.Append "Saldo", adDouble
rstemp.Open
Set DataGrid1.DataSource = rstemp
DataGrid1.Columns(0).Width = 2400
DataGrid1.Columns(1).Width = 1500
DataGrid1.Columns(2).Width = 2000
sentencia = "Tu sentencia"
Set rs1 = cn.Execute(sentencia) 'cn es de conecion ADO
Do Until rs1.EOF
monto=rs1(1)
rstemp.AddNew
rstemp(0) = rs1(0)
rstemp(0) = rs1(1)
rstemp(3) = monto
monto=monto+monto
rstemp.Update
rs1.MoveNext
Loop
Espero que te sirva saludos2
