(1/8+2/9-1/4)×5(целых)1/7:(7/9-2/3+1/6) по действиям
1.- 1/8 + 2/9 = 25/72 2.- 25/72 - 1/4 = 7/72 3.- 7/9 - 2/3 = 1/9 4.- 1/9 + 1/6 = 2-3/18 = -1/18