ГДЗ Математика 6 клас Істер — Вправа 264

1) $\frac{7}{36} + \frac{1}{5} + \frac{5}{36} = (\frac{7}{36} + \frac{5}{36}) + \frac{1}{5} = \frac{12}{36} + \frac{1}{5} =$

$= \frac{1}{3} + \frac{1}{5} = \frac{5}{15} + \frac{3}{15} = \frac{8}{15};$

2) $\frac{5}{16} + \frac{4}{25} + \frac{3}{16} + \frac{6}{25} = (\frac{5}{16} + \frac{3}{16}) + (\frac{4}{25} + \frac{6}{25}) =$

$= \frac{8}{16} + \frac{10}{25} = \frac{1}{2} + \frac{2}{5} = \frac{5}{10} + \frac{4}{10} = \frac{9}{10};$

3) $\frac{19}{42} - (\frac{5}{42} + \frac{1}{5}) = (\frac{19}{42} - \frac{5}{42}) - \frac{1}{5} = \frac{14}{42} - \frac{1}{5} =$

$= \frac{1}{3} - \frac{1}{5} = \frac{5}{15} - \frac{3}{15} = \frac{2}{15};$

4) $(\frac{1}{6} + \frac{7}{15}) - \frac{2}{15} = \frac{1}{6} + (\frac{7}{15} - \frac{2}{15}) = \frac{1}{6} + \frac{5}{15} =$

$= \frac{1}{6} + \frac{1}{3} = \frac{1}{6} + \frac{2}{6} = \frac{3}{6} = \frac{1}{2}.$