1) $5 - 2\frac{3}{7} = 4\frac{7}{7} - 2\frac{3}{7} = 2\frac{4}{7}$
2) $2\frac{4}{7} : 1\frac{2}{7} = \frac{18}{7} : \frac{9}{7} = \frac{18}{7} * \frac{7}{9} = \frac{2}{1} * \frac{1}{1} = 2$
3) $2 : 1\frac{1}{3} = 2 : \frac{4}{3} = 2 * \frac{3}{4} = \frac{3}{2} = 1\frac{1}{2}$
4) $\frac{17}{18} : 1\frac{1}{2} = \frac{17}{18} : \frac{3}{2} = \frac{17}{18} * \frac{2}{3} = \frac{17}{9} * \frac{1}{3} = \frac{17}{27}$
5) $5 * \frac{2}{9} = \frac{10}{9} = 1\frac{1}{9}$
6) $1\frac{1}{9} - \frac{17}{18} = 1\frac{2}{18} - \frac{17}{18} = \frac{20}{18} - \frac{17}{18} = \frac{3}{18} = \frac{1}{6}$
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