12000-1+2000-300+100-5000 120+300-1000+300-299 1200+30+20+90-4000 300-400+200-1000 200-100-100-200-100 102-300-2000-10

Первый пример.

12 000 - 1 + 2000 - 300 + 100 - 5000 = 8799;

12 000 - 1 = 11 999;

11 999 + 2000 = 13 999;

13 999 - 300 = 13 699;

13 699 + 100 = 13 799;

13 799 - 5000 = 8799.

Второй пример.

120 + 300 - 1000 + 300 - 299 = - 579;

120 + 300 = 420;

420 - 1000 = - 580;

-580 + 300 = - 280;

-280 - 299 = - 579.

Третий пример.

1200 + 30 + 20 + 90 - 4000 = - 2660;

1200 + 30 = 1230;

1230 + 20 = 1250;

1250 + 90 = 1340;

1340 - 4000 = - 2660.

Четвертый пример.

300 - 400 + 200 - 1000 = - 900;

300 - 400 = - 100;

-100 + 200 = 100;

100 - 1000 = - 900.

Пятый пример.

200 - 100 - 100 - 200 - 100 = - 300;

200 - 100 = 100;

100 - 100 = 0;

0 - 200 = - 200;

-200 - 100 = - 300.

Шестой пример.

102 - 300 - 2000 - 10 = - 2208

102 - 300 = - 198;

-198 - 2000 = 2198;

-2198 - 10 = - 2208.