12\frac{9}{13}-8=4\frac{9}{13}
7-3\frac{5}{11}=3\frac{6}{11}
3\frac{2}{3}+\frac{5}{7}=3\frac{14}{21}+\frac{15}{21}=3\frac{29}{21}=4\frac{8}{21}
2\frac{3}{8}+4\frac{4}{5}=2\frac{15}{40}+4\frac{32}{40}=6\frac{47}{40}=7\frac{7}{40}
7\frac{3}{4}-5\frac{2}{3}=7\frac{9}{12}-5\frac{8}{12}=2\frac{1}{12}
8\frac{1}{5}-4\frac{5}{6}=8\frac{6}{30}-4\frac{25}{30}=7\frac{36}{30}-4\frac{25}{30}=3\frac{11}{30}
1\frac{6}{9}+3\frac{11}{18}=1\frac{12}{18}+3\frac{11}{18}=4\frac{23}{18}=5\frac{5}{18}
5\frac{2}{7}-1\frac{9}{21}=5\frac{6}{21}-1\frac{9}{21}=4\frac{27}{21}-1\frac{9}{21}=3\frac{18}{21}=3\frac{6}{7}