0;
-3;
20  +  15;
20 - 3 * (4 -2);
1 + 2 + 3 + 5 + 6;
1 * 2 * 3 * 4 * 5;
(1 + 2) +3 * 5 + (10-2);
20 * -3;
(100 - (10-4*(6-3)));
(15 - 4) * 9 * (103 - 78) - 45;
