1) 1 1/3- 2 1/3+ 3 2/5 2) 1- 3/5- 2/5 3) 6/7- 1 2/9+ 1/7 4) -1 2/3+ 3 1/6- 2 1/12 5)...

1) $1 \frac{1}{3} -2 \frac{1}{3} +3 \frac{2}{5} = \frac{4}{3} - \frac{7}{3} + \frac{17}{5} = \frac{20-35+51}{15} = \frac{36}{15} =2,4$
2) $1-\frac{3}{5} - \frac{2}{5} = \frac{5-3-2}{5} = \frac{0}{5} =0$
3) $\frac{6}{7} -1 \frac{2}{9} + \frac{1}{7} = \frac{6}{7} - \frac{11}{9} + \frac{1}{7} = \frac{54-77+9}{63} = \frac{-14}{63}= -0,(2)$
4) $-1 \frac{2}{3} +3 \frac{1}{6} -2 \frac{1}{12} =- \frac{5}{3} + \frac{19}{6} - \frac{25}{12} = \frac{-20+38-25}{12} = \frac{-7}{12} =-0,6$
5) $-7+6 \frac{1}{2} = -7+\frac{13}{2} = \frac{-14+13}{2} = \frac{-1}{2} =-0,5$
6) $3 \frac{2}{5} -4 \frac{1}{5} = \frac{17}{5} - \frac{21}{5} = \frac{17-21}{5} = \frac{-4}{5} =-0,8$
7) $\frac{2}{9} + \frac{1}{3} - \frac{7}{27} +1 \frac{31}{36} = \frac{2+3}{9} - \frac{7}{27} + \frac{67}{36} = \frac{15-7}{27} + \frac{67}{36} = \frac{8}{27} + \frac{67}{36}= \frac{288+1809}{972}$ $= \frac{2097}{972} =2,16$
8) $-1- \frac{2}{5} - \frac{7}{10} = \frac{-10-4-7}{10} = \frac{-21}{10} =-2,1$