1\frac{2}{7}+\frac{1}{4}=1\frac{8}{28}+\frac{7}{28}=1\frac{15}{28}
15*4\frac{2}{3}=\frac{15*14}{3}=\frac{5*14}{1}=70
1\frac{3}{4}+3\frac{3}{5}=1\frac{15}{20}+3\frac{12}{20}=4\frac{27}{20}=5\frac{7}{20}
1\frac{1}{3}*\frac{3}{34}=\frac{4*3}{3*34}=\frac{2}{17}
5\frac{2}{3}-4\frac{2}{5}=5\frac{10}{15}-4\frac{6}{15}=1\frac{4}{15}
3\frac{3}{4}:12=\frac{15}{4}*\frac{1}{12}=\frac{5}{16}
7\frac{1}{8}-\frac{5}{34}=7\frac{17}{136}-\frac{20}{136}=6\frac{153}{136}-\frac{20}{136}=6\frac{133}{136}
7\frac{1}{3}:1\frac{4}{7}=\frac{22}{3}*\frac{7}{11}=\frac{14}{3}=4\frac{2}{3}