protected function col_number($questionstat) {
        if ($this->is_calculated_question_summary($questionstat)) {
            return '';
        }
        if (!isset($questionstat->question->number)) {
            return '';
        }
        $number = $questionstat->question->number;

        if (isset($questionstat->subqdisplayorder)) {
            $number = $number . '.'.$questionstat->subqdisplayorder;
        }

        if ($questionstat->question->qtype != 'random' && !is_null($questionstat->variant)) {
            $number = $number . '.'.$questionstat->variant;
        }

        return $number;
    }