OK, let's crack this. We're given 105 and our task is to multiply it by 83. Essentially, we'll be adding 105 to itself 83 times.
Step 1: 0 + 105 = 105
Step 2: 105 + 105 = 210
Step 3: 210 + 105 = 315
Step 4: 315 + 105 = 420
Step 5: 420 + 105 = 525
Step 6: 525 + 105 = 630
Step 7: 630 + 105 = 735
Step 8: 735 + 105 = 840
Step 9: 840 + 105 = 945
Step 10: 945 + 105 = 1050
Step 11: 1050 + 105 = 1155
Step 12: 1155 + 105 = 1260
Step 13: 1260 + 105 = 1365
Step 14: 1365 + 105 = 1470
Step 15: 1470 + 105 = 1575
Step 16: 1575 + 105 = 1680
Step 17: 1680 + 105 = 1785
Step 18: 1785 + 105 = 1890
Step 19: 1890 + 105 = 1995
Step 20: 1995 + 105 = 2100
Step 21: 2100 + 105 = 2205
Step 22: 2205 + 105 = 2310
Step 23: 2310 + 105 = 2415
Step 24: 2415 + 105 = 2520
Step 25: 2520 + 105 = 2625
Step 26: 2625 + 105 = 2730
Step 27: 2730 + 105 = 2835
Step 28: 2835 + 105 = 2940
Step 29: 2940 + 105 = 3045
Step 30: 3045 + 105 = 3150
Step 31: 3150 + 105 = 3255
Step 32: 3255 + 105 = 3360
Step 33: 3360 + 105 = 3465
Step 34: 3465 + 105 = 3570
Step 35: 3570 + 105 = 3675
Step 36: 3675 + 105 = 3780
Step 37: 3780 + 105 = 3885
Step 38: 3885 + 105 = 3990
Step 39: 3990 + 105 = 4095
Step 40: 4095 + 105 = 4200
Step 41: 4200 + 105 = 4305
Step 42: 4305 + 105 = 4410
Step 43: 4410 + 105 = 4515
Step 44: 4515 + 105 = 4620
Step 45: 4620 + 105 = 4725
Step 46: 4725 + 105 = 4830
Step 47: 4830 + 105 = 4935
Step 48: 4935 + 105 = 5040
Step 49: 5040 + 105 = 5145
Step 50: 5145 + 105 = 5250
Step 51: 5250 + 105 = 5355
Step 52: 5355 + 105 = 5460
Step 53: 5460 + 105 = 5565
Step 54: 5565 + 105 = 5670
Step 55: 5670 + 105 = 5775
Step 56: 5775 + 105 = 5880
Step 57: 5880 + 105 = 5985
Step 58: 5985 + 105 = 6090
Step 59: 6090 + 105 = 6195
Step 60: 6195 + 105 = 6300
Step 61: 6300 + 105 = 6405
Step 62: 6405 + 105 = 6510
Step 63: 6510 + 105 = 6615
Step 64: 6615 + 105 = 6720
Step 65: 6720 + 105 = 6825
Step 66: 6825 + 105 = 6930
Step 67: 6930 + 105 = 7035
Step 68: 7035 + 105 = 7140
Step 69: 7140 + 105 = 7245
Step 70: 7245 + 105 = 7350
Step 71: 7350 + 105 = 7455
Step 72: 7455 + 105 = 7560
Step 73: 7560 + 105 = 7665
Step 74: 7665 + 105 = 7770
Step 75: 7770 + 105 = 7875
Step 76: 7875 + 105 = 7980
Step 77: 7980 + 105 = 8085
Step 78: 8085 + 105 = 8190
Step 79: 8190 + 105 = 8295
Step 80: 8295 + 105 = 8400
Step 81: 8400 + 105 = 8505
Step 82: 8505 + 105 = 8610
Step 83: 8610 + 105 = 8715

So, 105*83 = 8715