$(\frac{2}{7} + \frac{3}{7} + \frac{4}{9} + \dots + \frac{101}{104}) + (\frac{5}{7} + \frac{5}{8} + \frac{5}{9} + \dots + \frac{5}{104}) = $

$1\frac{1}{10} + 2\frac{2}{10} + 3\frac{3}{10} + \dots + 9\frac{9}{10} = $

$-2\frac{1}{3} - 3\frac{1}{2} \times 1\frac{1}{5} \div 2\frac{1}{2} - 1\frac{1}{2} = $

$\frac{1}{1 - \frac{1}{1 - \frac{1}{1 - \frac{1}{3}}}} = $

$\frac{3}{20 \times 21} + \frac{3}{21 \times 22} + \dots + \frac{3}{59 \times 40} = $