1. 648720 : 68 + 506 * 108 - 63295 = 9540 + 54648 - 63295 = 8893
2. 608506 - 236 * 400 + 8716 = 608506 - 94400 + 8716 = 522822
3. 286996 : (1010 - 553) + 164268 : 324 = 286996 : 457 + 507 = 628 + 507 = 1135
4. 1000000 - (700800 + 425 * 704) + 25 = 1000000 - (700800 + 299200) + 25 = 1000000 - 1000000 + 25 = 25