Это очень срочно
(0.8+(-1/6))+(-2 1/3)

(0,8+(-1/6))+(-2 1/3)==(4/5-1/6)+(-2 1/3) == (24/30-5/30)-2 1/3= = 19/30-2 1/3== 19/30-2 10/30== –(2 10/30 - 19/30) == – (1 40/30 - 19/30) == – 1 21/30 = -1 7/10 = -1,7