Question

Тот кто не знает пусть не пишет!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

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Answer 2

$\tt\displaystyle 1) \frac{2}{15} + \frac{4}{9} + \frac{5}{12} = \frac{24+80+75}{180} = \frac{179}{180} \\\\ 2) \frac{3}{5} - \frac{11}{25} + \frac{4}{15} = \frac{45-33+20}{75} = \frac{32}{75} \\\\ 3) (\frac{8}{21} - \frac{3}{14}) + \frac{4}{15} = (\frac{16 - 9}{42}) + \frac{4}{15} = \frac{7}{42} + \frac{4}{15} = \frac{1}{6} + \frac{4}{15} = \frac{5+8}{30} = \frac{13}{30} \\\\ 4) (\frac{5}{12} - \frac{2}{9}) + (\frac{7}{36} - \frac{5}{54}) = (\frac{15-8}{36}) + (\frac{21-10}{108}) = \frac{7}{36} + \frac{11}{108} = \frac{21+11}{108} = \\\\ = \frac{32}{108} = \frac{8}{27}$