18 * 9 + 32 * 9 = (18 + 32) * 9 = 50 * 9 = 5 * 9 * 10 = 45 * 10 = 450;
75 : 15 − 15 : 5 = 5 − 3 = 2;
3 * (7 * 8 + 52) = 3 * (56 + 52) = 3 * 108 = (100 + 8) * 3 = 100 * 3 + 8 * 3 = 300 + 24 = 324;
(12 − 4) * (80 : 1) = 8 * 80 = 8 * 8 * 10 = 64 * 10 = 640;
24 * 7 : 4 − 4 * 3 = (20 + 4) * 7 : 4 − 12 = (20 * 7 + 4 * 7) : 4 − 12 = (140 + 28) : 4 − 12 = 168 : 4 − 12 = (160 + 8) : 4 − 12 = (160 : 4 + 8 : 4) − 12 = (40 + 2) − 12 = 42 − 12 = 30;
50 + 18 * (64 : 16) = 50 + 18 * 4 = 50 + (10 + 8) * 4 = 50 + 10 * 4 + 8 * 4 = 50 + 40 + 32 = 90 + 32 = 122.