Resposta:

Explicação passo a passo:

a.

1/5+1/6=

1/5=6/30

1/6=5/30

1/5+1/6=

6/30+5/30=

11/30

b.

(-1/2).(-7/2).(-2/1)=

(+7/4).(-2/1)=

-14/4= [simplifica por 2]

-7/2

c.

(-4/6)-8/3=

8/3=16/6

(-4/6)-8/3=

(-4/6)-16/6=

-20/6= [simplifica por 2]

-10/3

d.

5/6-(-1/5)=

5/6=25/30

1/5=6/30

5/6-(-1/5)=

5/6+1/5=

25/30+6/30=

31/30