unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DBCtrls, StdCtrls, Mask, ExtCtrls, DB, DBTables;

type
  TForm1 = class(TForm)
    Table1: TTable;
    Table2: TTable;
    DataSource1: TDataSource;
    DataSource2: TDataSource;
    DBNavigator1: TDBNavigator;
    Panel1: TPanel;
    Panel2: TPanel;
    Panel3: TPanel;
    Panel4: TPanel;
    Panel5: TPanel;
    DBEdit1: TDBEdit;
    DBEdit2: TDBEdit;
    DBEdit3: TDBEdit;
    DBEdit4: TDBEdit;
    DBLookupComboBox1: TDBLookupComboBox;
    Table1Goods: TStringField;
    Table1Price: TSmallintField;
    Table1Amount: TSmallintField;
    Table1Total: TSmallintField;
    Table1People: TStringField;
    procedure Table1CalcFields(DataSet: TDataSet);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Table1CalcFields(DataSet: TDataSet);
begin
table1.Fields[3].Value:=table1.Fields[1].Value*table1.Fields[2].Value;
end;

end.