(6 7/12-3 17/36)∙1/2-4 1/3:13/20.

$(6 \frac{7}{12} - 3 \frac{17}{36}) * \frac{1}{2} - 4 \frac{1}{3}: \frac{13}{20} = \\ \\ ( \frac{79}{12} - \frac{125}{36} ) * \frac{1}{2} - \frac{13}{3} : \frac{13}{20} = \\ \\ ( \frac{237^|^3}{36}- \frac{125^|^1}{36} ) * \frac{1}{2} - \frac{13}{3} : \frac{13}{20} = \\ \\ \frac{112}{36}* \frac{1}{2} - \frac{13}{3} : \frac{13}{20} = \\ \\ \frac{112*1}{36*2} -\frac{13}{3} : \frac{13}{20} = \\ \\ \frac{112}{72} - \frac{13}{3} : \frac{13}{20}=$
$\frac{112}{72} - \frac{13}{3} : \frac{13}{20} = \\ \\ \frac{112}{72} - \frac{13}{3}* \frac{20}{13} = \\ \\ \frac{112}{72} - \frac{13}{3}* \frac{20}{3} = \\ \\ \frac{14}{9} -\frac{60}{9} = -5 \frac{1}{9}; \\ \\ \\ OTBET: - 5 \frac{1}{9}$