6684: 6+5 339 -3*289 1890*3650 - 9312: 388+999

6 684:6+5 339 -3*289 = 5586
1) 6684 : 6 = 1114
2) 3*289 = 867
3) 1114 + 5339 = 6453
4) 6453 - 867 = 5586

1890*3650 - 9312:388+999 = 6899475
1) 1890 * 3650 = 6898500
2) 9312 : 388 = 24
3) 6898500 - 24 = 6898476
4) 6898476 + 999 = 6899475