public function fleschKincaidReadingEase($strText = false)
    {
        $strText = $this->setText($strText);

        $score = Maths::bcCalc(
            Maths::bcCalc(
                206.835,
                '-',
                Maths::bcCalc(
                    1.015,
                    '*',
                    Text::averageWordsPerSentence($strText, $this->strEncoding)
                )
            ),
            '-',
            Maths::bcCalc(
                84.6,
                '*',
                Syllables::averageSyllablesPerWord($strText, $this->strEncoding)
            )
        );

        if ($this->normalise) {
            return Maths::normaliseScore($score, 0, 100, $this->dps);
        } else {
            return Maths::bcCalc($score, '+', 0, true, $this->dps);
        }
    }