Выполните вычисление
1/3-(+2/3)=
-2/5-(-3/5)=
-3/7-(+4/7)=
-2/5-(-3/5)=
5/8-(-7/8)=
-1/9-(+2/9)=

1/3 - (+2/3)  =1/3   -  2/3  = - (2/3   -  1/3)  = - 1/3-2/5 -(-3/5) =  - 2/5  + 3/5  = 3/5   - 2/5  = 1/5-3/7 - (+4/7) = - 3/7   - 4/7  = - (3/7 + 4/7) = - 7/7  = -1-2/5 - (-3/5) =- 2/5  + 3/5  = 1/55/8 - (-7/8) = 5/8  + 7/8  = 12/8  = 3/2  = 1  1/2- 1/9  -(+2/9) = - 1/9   - 2/9  = -(1/9 + 2/9) = - 3/9   = - 1/3