1080-789=291...............
(3/4 - 1 7/8) : 3/4 + 3 1/9 * 3/7 = -1/6
1) 3/4 - 1 7/8 = 3/4 - 15/8 = (6-15)/8 = -9/8
2) -9/8 : 3/4 = - (9*4)/(8*3) = - 36/24 = -3/2
3) 3 1/9 * 37 = 28/9 * 3/7 = 4/3
4) -3/2 + 4/3 = (-9+8)/6 = -1/6
Ответ: -1/6
460+500=960. 180-90=90. 459-9=450
90+80=170. 540-300=240. 709+80=789
870-50=820. 830+70=900. 89+700=789