Задание 873 (3;4) пожалуйста помогите!!!

$1)2 \frac{7}{15} - \frac{5}{12} =2 \frac{28}{60} - \frac{25}{60} =2 \frac{3}{60} =2 \frac{1}{20} \\ 2)4 \frac{1}{10} :2 \frac{1}{20} = \frac{41}{10} : \frac{41}{20} = \frac{41}{10} * \frac{20}{41} =2 \\ 3)2* \frac{5}{6} = \frac{5}{3} =1 \frac{2}{3} \\ 4)2 \frac{1}{3} +1 \frac{2}{3} =4$
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$1)2 \frac{1}{6} + \frac{8}{15} =2 \frac{5}{30} + \frac{16}{30} =2 \frac{21}{30} =2 \frac{7}{10} \\ 2)1 \frac{1}{2} :2 \frac{7}{10} = \frac{3}{2} : \frac{27}{10} = \frac{3}{2} * \frac{10}{27} = \frac{5}{9} \\ 3) \frac{5}{9} *1 \frac{4}{5} = \frac{5}{9} * \frac{9}{5} =1 \\ 4)4 \frac{5}{12} -1=3 \frac{5}{12}$