Помогите пожалуйста умоляю решить

$1) \frac{7}{15} - \frac{3}{40} = \frac{56}{120} - \frac{9}{120} = \frac{47}{120} \\$
$2) \frac{47}{120} - \frac{1}{24} = \frac{47}{120} - \frac{5}{120} = \frac{42}{120} =$
$= \frac{7}{20}$
$3) \frac{7}{20} \div \frac{7}{10} = \frac{7}{20} \times \frac{10}{7} = \frac{1}{2}$
$4) \frac{24}{10} \times \frac{1}{3} = \frac{8}{10} = \frac{4}{5}$
$5) \frac{4}{5} - 3 = \frac{4}{5} - 2 \frac{5}{5} = - 2 \frac{1}{5}$
$6) - 2 \frac{1}{5} \times \frac{5}{11} = - \frac{11}{5} \times \frac{5}{11} = - 1$
$7)\frac{1}{2} \div ( - 1) = - 1 \frac{1}{2}$
$8) \frac{3}{4} - 1 \frac{2}{3} = \frac{9}{12} - 1 \frac{8}{12} = \frac{9}{12} - \frac{20}{12} =$
$= - \frac{11}{12}$
$9)1 \frac{5}{6} \div ( - \frac{11}{12} ) = \frac{11}{6} \times ( - \frac{12}{11} ) = \\ = - 2$
$10) \frac{4}{9} - \frac{5}{12} = \frac{16}{36} - \frac{15}{36} = \frac{1}{36}$
$11) \frac{1}{36} + \frac{75}{100} = \frac{1}{36} + \frac{3}{4} = \frac{1}{36} + \frac{27}{36} =$
$= \frac{28}{36} = \frac{7}{9}$
75/100 сократили на 25, то есть разделили числитель и знаменатель на 25
$11) \frac{7}{9} \times \frac{3}{7} = \frac{1}{3}$
$12) - 2 \div \frac{1}{3} = - 2 \times \frac{3}{1} = - 6$
$13) - 1 \frac{1}{2} \times ( - 6) = - \frac{3 }{2} \times ( - \frac{6}{1} ) =$
$= 9$
Ответ:9