8 1/2-3 1/2:( 2 1/2+1 3/4)*2 3/7

Решите задачу:

$8 \frac{1}{2} - 3 \frac{1}{2} \div (2 \frac{1}{2} + 1 \frac{3}{4} ) \times 2 \frac{3}{7} = \frac{17}{2} - \frac{7}{2} \div ( \frac{5}{2} + \frac{7}{4} ) \times \frac{17}{7} = \frac{17}{2} - \frac{7}{2} \div ( \frac{10}{4} + \frac{7}{4} ) \times \frac{17}{7} = \frac{17}{2} - \frac{7}{2} \div \frac{17}{4} \times \frac{17}{7} = \frac{17}{2} - \frac{7}{2} \times \frac{4}{17} \times \frac{17}{7} = \frac{17}{2} - 2 = \frac{17}{2} - \frac{4}{2} = \frac{13}{2} = 6\frac{1}{2}$