1. Выполни действия: a) $$\frac{15}{19} - \frac{7}{19} + \frac{4}{19}$$; в) $$5 - 2\frac{4}{11}$$; б) $$7\frac{5}{14} + 3\frac{11}{14}$$; г) $$8\frac{2}{9} - 2\frac{4}{9}$$

a) $$\frac{15}{19} - \frac{7}{19} + \frac{4}{19} = \frac{15-7+4}{19} = \frac{12}{19}$$

в) $$5 - 2\frac{4}{11} = 5 - \frac{2\cdot11 + 4}{11} = 5 - \frac{26}{11} = \frac{5 \cdot 11}{11} - \frac{26}{11} = \frac{55-26}{11} = \frac{29}{11} = 2\frac{7}{11}$$

б) $$7\frac{5}{14} + 3\frac{11}{14} = (7+3) + (\frac{5}{14} + \frac{11}{14}) = 10 + \frac{5+11}{14} = 10 + \frac{16}{14} = 10 + \frac{8}{7} = 10 + 1\frac{1}{7} = 11\frac{1}{7}$$

г) $$8\frac{2}{9} - 2\frac{4}{9} = (8-2) + (\frac{2}{9} - \frac{4}{9}) = 6 - \frac{2}{9} = 5\frac{9}{9} - \frac{2}{9} = 5\frac{7}{9}$$

Ответы:

• а) $$\frac{12}{19}$$
• в) $$2\frac{7}{11}$$
• б) $$11\frac{1}{7}$$
• г) $$5\frac{7}{9}$$