Вычислите значение выражения:
1) $-\frac{1}{4} + \frac{3}{5}$;
2) $\frac{9}{11} + (-\frac{2}{5})$;
3) $-\frac{20}{21} + \frac{3}{7}$;
4) $-8\frac{9}{14} + 3\frac{3}{7}$;
5) $7\frac{5}{12} + (-3\frac{7}{24})$;
6) $-6\frac{11}{12} + (-8\frac{13}{18})$;
7) $-5\frac{12}{35} + 10$;
8) $-11\frac{7}{9} + 8\frac{2}{15}$;
9) $-3\frac{1}{12} + \frac{1}{6}$;
10) $3\frac{6}{7} + (-6\frac{4}{9})$;
11) $9\frac{1}{6} + (-5\frac{3}{4})$;
12) $-3\frac{8}{9} + (-2\frac{1}{12})$.
$-\frac{1}{4} + \frac{3}{5} = -\frac{5}{20} + \frac{12}{20} = \frac{7}{20}$
$\frac{9}{11} + (-\frac{2}{5}) = \frac{45}{55} + (-\frac{22}{55}) = \frac{23}{55}$
$-\frac{20}{21} + \frac{3}{7} = -\frac{20}{21} + \frac{9}{21} = -(\frac{20}{21} - \frac{9}{21}) = -\frac{11}{21}$
$-8\frac{9}{14} + 3\frac{3}{7} = -8\frac{9}{14} + 3\frac{6}{14} = -(8\frac{9}{14} - 3\frac{6}{14}) = -5\frac{3}{14}$
$7\frac{5}{12} + (-3\frac{7}{24}) = 7\frac{10}{24} - 3\frac{7}{24} = 4\frac{3}{24} = 4\frac{1}{8}$
$-6\frac{11}{12} + (-8\frac{13}{18}) = -(6\frac{33}{36} + 8\frac{26}{36}) = -14\frac{59}{36} = -15\frac{23}{36}$
$-5\frac{12}{35} + 10 = 9\frac{35}{35} - 5\frac{12}{35} = 4\frac{23}{35}$
$-11\frac{7}{9} + 8\frac{2}{15} = -(11\frac{35}{45} - 8\frac{6}{45}) = -3\frac{29}{45}$
$-3\frac{1}{12} + \frac{1}{6} = -(3\frac{1}{12} - \frac{2}{12}) = -(2\frac{13}{12} - \frac{2}{12}) = -2\frac{11}{12}$
$3\frac{6}{7} + (-6\frac{4}{9}) = -(6\frac{28}{63} - 3\frac{54}{63}) = -(5\frac{91}{63} - 3\frac{54}{63}) = -2\frac{37}{63}$
$9\frac{1}{6} + (-5\frac{3}{4}) = 9\frac{2}{12} - 5\frac{9}{12} = 8\frac{14}{12} - 5\frac{9}{12} = 3\frac{5}{12}$
$-3\frac{8}{9} + (-2\frac{1}{12}) = -(3\frac{32}{36} + 2\frac{3}{36}) = -5\frac{35}{36}$
Пожауйста, оцените решение