a)
[tex]1 \frac{2}{9} + 1 \frac{5}{9} = 2 \frac{7}{9} [/tex]
[tex]2 \frac{7}{9} - 1 \frac{6}{9} = 1 \frac{1}{9} [/tex]
[tex]1 \frac{1}{9} + 2 \frac{5}{9} = 3 \frac{6}{9} [/tex]
[tex]3 \frac{6}{9} - 1 \frac{4}{9} = 2 \frac{2}{9} [/tex]
b)
[tex]3 \frac{7}{11} - 1 \frac{4}{11} = 2 \frac{3}{11} [/tex]
[tex]2 \frac{3}{11} + 1 \frac{7}{11} = 3 \frac{10}{11} [/tex]
[tex]3 \frac{10}{11} - 2 \frac{8}{11} = 1 \frac{2}{11} [/tex]
[tex]1 \frac{2}{11} + 3 \frac{6}{11} = 4 \frac{8}{11} [/tex]
