2. Найдите значение выражений. a)5 11 −3 11 +7 11 б) 913 19+(818 19−315 19) B) 184 21−(1010 21+319 21)

2. Найдите значение выражений.

a) $$\frac{5}{11} - \frac{3}{11} + \frac{7}{11}$$

$$\frac{5 - 3 + 7}{11} = \frac{9}{11}$$

б) $$9\frac{13}{19} + (8\frac{18}{19} - 3\frac{15}{19})$$

$$9\frac{13}{19} + 8\frac{18}{19} - 3\frac{15}{19} = (9 + 8 - 3) + (\frac{13}{19} + \frac{18}{19} - \frac{15}{19}) = 14 + \frac{13 + 18 - 15}{19} = 14 + \frac{16}{19} = 14\frac{16}{19}$$

в) $$18\frac{4}{21} - (10\frac{10}{21} + 3\frac{19}{21})$$

$$18\frac{4}{21} - 10\frac{10}{21} - 3\frac{19}{21} = (18 - 10 - 3) + (\frac{4}{21} - \frac{10}{21} - \frac{19}{21}) = 5 + \frac{4 - 10 - 19}{21} = 5 + \frac{-25}{21} = 5 - \frac{25}{21} = 5 - 1\frac{4}{21} = 4 - \frac{4}{21} = 3\frac{21}{21} - \frac{4}{21} = 3\frac{17}{21}$$

Ответ: a) $$\frac{9}{11}$$; б) $$14\frac{16}{19}$$; в) $$3\frac{17}{21}$$