1. Выполните действия: a) 10 - 4 + 3 ; 11 11 11 б) 4 +3 ; 9 9 в) 6-2; г) 5-13-11

a) $$10\frac{4}{11} + \frac{3}{11} = \frac{10 \cdot 11 + 4}{11} + \frac{3}{11} = \frac{110 + 4}{11} + \frac{3}{11} = \frac{114}{11} + \frac{3}{11} = \frac{114 + 3}{11} = \frac{117}{11} = 10\frac{7}{11}$$

б) $$4\frac{5}{9} + 3\frac{8}{9} = (4 + 3) + (\frac{5}{9} + \frac{8}{9}) = 7 + \frac{5+8}{9} = 7 + \frac{13}{9} = 7 + 1\frac{4}{9} = 8\frac{4}{9}$$

в) $$6 - 2\frac{3}{8} = 6 - \frac{2 \cdot 8 + 3}{8} = 6 - \frac{16 + 3}{8} = 6 - \frac{19}{8} = 6 - 2\frac{3}{8} = (6 - 2) - \frac{3}{8} = 4 - \frac{3}{8} = 3\frac{8}{8} - \frac{3}{8} = 3\frac{8-3}{8} = 3\frac{5}{8}$$

г) $$5\frac{6}{13} - 1\frac{11}{13} = (5-1) + (\frac{6}{13} - \frac{11}{13}) = 4 + (\frac{6-11}{13}) = 4 + (\frac{-5}{13}) = 4 - \frac{5}{13} = 3\frac{13}{13} - \frac{5}{13} = 3\frac{13-5}{13} = 3\frac{8}{13}$$

Ответ: a) $$10\frac{7}{11}$$; б) $$8\frac{4}{9}$$; в) $$3\frac{5}{8}$$; г) $$3\frac{8}{13}$$