Условие:

(Устно.)
600 : 3 + 7 * 5
600 : (3 + 7) * 5
40 * (168) * 2
40 * (168 * 2)

600 : 3 + 7 * 5 = 200 + 35 = 235
600 : (3 + 7) * 5 = 600 : 10 * 5 = 60 * 5 = 300
40 * (168) * 2 = 40 * 8 * 2 = 320 * 2 = 640
40 * (168 * 2) = 40 * (1616) = 40 * 0 = 0