(40 * 3 + 360) : (2 400 : 12 - 6 * 15 + 25 * 2) * (530 - 380) - 170 = 280
1) 40 * 3 = 120
2) 120 + 360 = 480
3) 2 400 : 12 = 200
4) 6 * 15 = 90
5) 25 * 2 = 50
6) 200 - 90 = 110
7) 110 + 50 = 160
8) 530 - 380 = 150
9) 480 : 160 = 3
10) 3 * 150 = 450
11) 450 - 170 = 280
4/7 от 280 = 280 : 7 * 4 = 160