(3 5/6-2/60)+4 2 1/7+(4/7+1 2/7) 6 2/5-(1 3/5-1/5) (3 7/8+1/8)-2 5/8 7/9+(1 2/9-5/9) (4...

1)
$(3 \frac{5}{6} - \frac{2}{60} )+4=(3 \frac{50}{60} - \frac{2}{60} )+4=3 \frac{48}{60}+4=7 \frac{4}{5}$
2)
$2 \frac{1}{7} +( \frac{4}{7} +1 \frac{2}{7} )=2 \frac{1}{7} +1 \frac{6}{7} =3 \frac{7}{7} =4$
3)
$6 \frac{2}{5} -(1 \frac{3}{5} - \frac{1}{5} )=6 \frac{2}{5} -1 \frac{2}{5}=5$
4)
$(3 \frac{7}{8} + \frac{1}{8} )-2 \frac{5}{8} =3 \frac{8}{8} -2 \frac{5}{8} =1 \frac{3}{8}$
5)
$\frac{7}{9} +(1 \frac{2}{9} - \frac{5}{9} )= \frac{7}{9} +( \frac{11}{9} - \frac{5}{9} )= \frac{7}{9} +\frac{6}{9}= \frac{13}{9} =1 \frac{4}{9}$
6)
$(4 \frac{2}{5} + \frac{4}{5} )+1 \frac{4}{5} =4 \frac{6}{5} +1 \frac{4}{5}=5 \frac{1}{5}+1 \frac{4}{5} =6 \frac{5}{5} =7$
7)
$6 \frac{1}{4} -(3 \frac{2}{4} +1 \frac{1}{4} )=6 \frac{1}{4} -4 \frac{3}{4} =5 \frac{5}{4} -4 \frac{3}{4}=1 \frac{2}{4} =1 \frac{1}{2}$
8)
$(5-2 \frac{3}{8} )- \frac{7}{8}=(4 \frac{8}{8} -2 \frac{3}{8})- \frac{7}{8} =2 \frac{5}{8}- \frac{7}{8}=1 \frac{13}{8} - \frac{7}{8}=1 \frac{6}{8}=1 \frac{3}{4}$