procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
  s: string;
begin
  if SpinEdit1.Value < 1 then Exit;
  Randomize;
  for i := 1 to SpinEdit1.Value do s := s + '9';
  Edit1.Text := IntToStr(Random(StrToInt(s)));
end;