250 + 250 * 2 = 250 + 500 = 750;
(250 + 250) * 2 = 500 * 2 = 1000;
(480 + 120) : 3 = 600 : 3 = 200;
60 + 90 : 10 * 3 = 60 + 9 * 3 = 60 + 27 = 87;
60 + 90 : (10 * 3) = 60 + 90 : 30 = 60 + 3 = 63;
120 − 80 : 4 * 5 = 120 − 20 * 5 = 120 − 100 = 20;
84 − 24 + 48 : 6 = 60 + 8 = 68;
84 − (24 + 48) : 6 = 84 − 72 : 6 = 84 − 12 = 72;
100 − 64 + 36 : 4 = 100 − 64 + 9 = 36 + 9 = 45.