4300-43*99= 128*32+872*32-1000*31= 728*359-628*359+641*1000=

1-ый пример.

4300 - 43 * 99 = 43;

43 * 99 = 4257;

4300 - 4257 = 43.

2-ой пример. 

128 * 32 + 872 * 32 - 1000 * 31 = 1000;

128 * 32 = 4096;

872 * 32 = 27 904;

4096 + 27 904 = 32 000;

1000 * 31 = 31 000;

32 000 - 31 000 = 1000.

3-ий пример.

728 * 359 - 628 * 359 + 641 * 1000 = 676 900;

728 * 359 = 261 352;

628 - 359 = 225 452;

261 352 - 225 452 = 35 900;

641 * 1000 = 641 000;

35 900 + 641 000 = 676 900.