а) (-1/2) + (1/2) = б) (2/3) + (-1/2) = 1/в) (-13/23) - (13/23) = -26/2г) (-3 2/3) - (-2 2/3) = -1 2/3 (или -5/3)
а) (-1/2) + (1/2) =
б) (2/3) + (-1/2) = 1/
в) (-13/23) - (13/23) = -26/2
г) (-3 2/3) - (-2 2/3) = -1 2/3 (или -5/3)