1) 812 - 907 = -95
2) 470 * 302 = 141940
3) 564 - 70 - 564 - 60 = (564 - 564) - (70 + 60) = 0 - 130 = -130
4) 809 * 62 + 809 * 38 = 809 * (62 + 38) = 809 * 100 = 80900
Ответ: 812 - 907 = -95; 470 * 302 = 141940; 564 - 70 - 564 - 60 = -130; 809 * 62 + 809 * 38 = 80900