public function isCorrectAnswer($answer)
    {

        $session = Controller::curr()->getRequest()->getSession();

        $v1 = $session->get("mathQuestionV1");
        $v2 = $session->get("mathQuestionV2");

        $session->clear('mathQuestionV1');
        $session->clear('mathQuestionV2');

        $word = MathSpamProtectorField::digit_to_word($v1 + $v2);

        return ($word == strtolower($answer) || ($this->config()->get('allow_numeric_answer') && (($v1 + $v2) == $answer)));
    }