1) 67812 - (489*105 + 7445) 2) (94554: 927+884)-109 3) 39405: 555+301*203 4) 346252: 428-18231: 309

67812 – (489 * 105 + 7445) = 9022
489 * 105 = 51345
51345 + 7445 = 58790
67812 - 58790 = 9022
 (94554 / 927 + 884) – 109 = 877
94554 / 927 = 102
102 + 884 = 986
986 - 109 = 877
39405 / 555 + 301*203 = 61174
39405 / 555 = 71
301 * 203 = 61103
71 + 61103 = 61174
346252 / 428 – 18231 / 309 = 750
346252 / 428 = 809
18231 / 309 = 59
809 - 59 = 750