2$$\frac{1}{3}$$ = $$\frac{2 \cdot 3 + 1}{3}$$ = $$\frac{7}{3}$$
3$$\frac{3}{8}$$ = $$\frac{3 \cdot 8 + 3}{8}$$ = $$\frac{27}{8}$$
1$$\frac{6}{7}$$ = $$\frac{1 \cdot 7 + 6}{7}$$ = $$\frac{13}{7}$$
$$\frac{4}{9} \cdot \frac{27}{8}$$ = $$\frac{4 \cdot 27}{9 \cdot 8}$$ = $$\frac{108}{72}$$ = $$\frac{3}{2}$$
$$\frac{13}{7} : \frac{26}{63}$$ = $$\frac{13}{7} \cdot \frac{63}{26}$$ = $$\frac{13 \cdot 63}{7 \cdot 26}$$ = $$\frac{819}{182}$$ = $$\frac{9}{2}$$
$$\frac{7}{3}$$ + $$\frac{3}{2}$$ - $$\frac{9}{2}$$ = $$\frac{7}{3}$$ + $$\frac{3 - 9}{2}$$ = $$\frac{7}{3}$$ - $$\frac{6}{2}$$ = $$\frac{7}{3}$$ - 3 = $$\frac{7 - 9}{3}$$ = -$$\frac{2}{3}$$
Ответ: -$$\frac{2}{3}$$