Вычислить. (1/8+2/9-1/4) * 5 1/7: (7/9-2/3+1/6)

(1/8 + 2/9 - 1/4) * 5 =

((9*1+8*2) / 8*9) - 1/4) * 5 =

(25/72 - 1/4) * 5 =

((25*4-1*72) / 72) * 5 =

7/72 * 5 =

7/72*5/1 = 35/72

1/7 : (7/9 - 2/3 + 1/6) =

1/7 : (((7 - 2*3) / 9) + 1/6) =

1/7 : (1/9 + 1/6) =

1/7 : ((6+9) / 9*6) =

1/7 : 15/54 =

1/7 * 54/15 = 18/35