[tex]a) \frac{1}{2}+ \frac{2}{3}= \frac{3}{6}+ \frac{4}{6}= \frac{7}{6} =1 \frac{1}{6} \\ b) \frac{3}{5} + \frac{4}{3}= \frac{9}{15}+ \frac{20}{15}= \frac{29}{15}=1 \frac{14}{15} \\ c) \frac{1}{9}+ \frac{7}{8}= \frac{8}{72}+\frac{63}{72}= \frac{71}{72} \\ d) \frac{2}{11} + \frac{3}{10} = \frac{20}{110} + \frac{33}{110}= \frac{55} {110}= \frac{1}{2} \\ e) \frac{5}{7} + \frac{3}{4} = \frac{20}{28} + \frac{21}{28} = \frac{41}{28}=1 \frac{13}{28} \\ [/tex]
[tex]f) \frac{11}{9}+ \frac{9}{11}= \frac{121}{99}+ \frac{81}{99}= \frac{202}{99}=2 \frac{4}{99} \\ g) \frac{13}{20} + \frac{21}{23} = \frac{299}{460} + \frac{420}{460} = \frac{719}{460} [/tex]
