1) Сократите дроби 7\21, 20\35, 48\72.2) Сравните дроби а) 4\9 и5\9, б)6\7 и 11\14, в)...

$1)\frac{7}{21} = \frac{1}{3}$

$\frac{20}{35}= \frac{4}{7}$

$\frac{48}{72} = \frac{2}{3}$

$2) \frac{4}{9} < \frac{5}{9}$

\frac{11}{14} " alt=" \frac{6}{7} > \frac{11}{14} " align="absmiddle" class="latex-formula">

\frac{5}{8} " alt=" \frac{2}{3} > \frac{5}{8} " align="absmiddle" class="latex-formula">

$3)\frac{5}{6} -7-18= \frac{5}{6} - \frac{42}{6} - \frac{108}{6} = -\frac{145}{6} =-24 \frac{1}{6}$

$\frac{1}{4} + \frac{2}{9} = \frac{9}{36}+\frac{8}{36} = \frac{17}{36}$

$\frac{2}{21} + \frac{9}{14} = \frac{4}{42} + \frac{27}{42} = \frac{31}{42}$

$4) \frac{5}{12} - \frac{1}{8} = \frac{10-3}{24} = \frac{7}{24}$ За второй день

$\frac{7}{24} + \frac{5}{12}= \frac{7+10}{24} = \frac{17}{24}$

$5)x-\frac{2}{5} = \frac{3}{7}- \frac{8}{35}$

$x = \frac{3}{7}- \frac{8}{35}+\frac{2}{5}$

$x = \frac{15-8+14}{35}= \frac{21}{35}$