Ответ:
а) \(\frac{2}{5}+1\frac{3}{8}=\frac{2}{5}+\frac{11}{8}=\frac{16}{40}+\frac{55}{40}=\frac{71}{40}=1\frac{31}{40}\).
б) \(\frac{3}{4}-\frac{2}{7}=\frac{21}{28}-\frac{8}{28}=\frac{13}{28}\).
в) \(\frac{3}{7}\cdot\frac{2}{11}=\frac{3\cdot2}{7\cdot11}=\frac{6}{77}\).
г) \(\frac{5}{8}:\frac{4}{9}=\frac{5}{8}\cdot\frac{9}{4}=\frac{45}{32}=1\frac{13}{32}\).
Ответ: а) \(1\frac{31}{40}\); б) \(\frac{13}{28}\); в) \(\frac{6}{77}\); г) \(1\frac{13}{32}\).
