Let's get this math done. We have 686 and we're going to multiply it by 105. This is the same as taking 686 and adding it to itself 105 times.
Step 1: 0 + 686 = 686
Step 2: 686 + 686 = 1372
Step 3: 1372 + 686 = 2058
Step 4: 2058 + 686 = 2744
Step 5: 2744 + 686 = 3430
Step 6: 3430 + 686 = 4116
Step 7: 4116 + 686 = 4802
Step 8: 4802 + 686 = 5488
Step 9: 5488 + 686 = 6174
Step 10: 6174 + 686 = 6860
Step 11: 6860 + 686 = 7546
Step 12: 7546 + 686 = 8232
Step 13: 8232 + 686 = 8918
Step 14: 8918 + 686 = 9604
Step 15: 9604 + 686 = 10290
Step 16: 10290 + 686 = 10976
Step 17: 10976 + 686 = 11662
Step 18: 11662 + 686 = 12348
Step 19: 12348 + 686 = 13034
Step 20: 13034 + 686 = 13720
Step 21: 13720 + 686 = 14406
Step 22: 14406 + 686 = 15092
Step 23: 15092 + 686 = 15778
Step 24: 15778 + 686 = 16464
Step 25: 16464 + 686 = 17150
Step 26: 17150 + 686 = 17836
Step 27: 17836 + 686 = 18522
Step 28: 18522 + 686 = 19208
Step 29: 19208 + 686 = 19894
Step 30: 19894 + 686 = 20580
Step 31: 20580 + 686 = 21266
Step 32: 21266 + 686 = 21952
Step 33: 21952 + 686 = 22638
Step 34: 22638 + 686 = 23324
Step 35: 23324 + 686 = 24010
Step 36: 24010 + 686 = 24696
Step 37: 24696 + 686 = 25382
Step 38: 25382 + 686 = 26068
Step 39: 26068 + 686 = 26754
Step 40: 26754 + 686 = 27440
Step 41: 27440 + 686 = 28126
Step 42: 28126 + 686 = 28812
Step 43: 28812 + 686 = 29498
Step 44: 29498 + 686 = 30184
Step 45: 30184 + 686 = 30870
Step 46: 30870 + 686 = 31556
Step 47: 31556 + 686 = 32242
Step 48: 32242 + 686 = 32928
Step 49: 32928 + 686 = 33614
Step 50: 33614 + 686 = 34300
Step 51: 34300 + 686 = 34986
Step 52: 34986 + 686 = 35672
Step 53: 35672 + 686 = 36358
Step 54: 36358 + 686 = 37044
Step 55: 37044 + 686 = 37730
Step 56: 37730 + 686 = 38416
Step 57: 38416 + 686 = 39102
Step 58: 39102 + 686 = 39788
Step 59: 39788 + 686 = 40474
Step 60: 40474 + 686 = 41160
Step 61: 41160 + 686 = 41846
Step 62: 41846 + 686 = 42532
Step 63: 42532 + 686 = 43218
Step 64: 43218 + 686 = 43904
Step 65: 43904 + 686 = 44590
Step 66: 44590 + 686 = 45276
Step 67: 45276 + 686 = 45962
Step 68: 45962 + 686 = 46648
Step 69: 46648 + 686 = 47334
Step 70: 47334 + 686 = 48020
Step 71: 48020 + 686 = 48706
Step 72: 48706 + 686 = 49392
Step 73: 49392 + 686 = 50078
Step 74: 50078 + 686 = 50764
Step 75: 50764 + 686 = 51450
Step 76: 51450 + 686 = 52136
Step 77: 52136 + 686 = 52822
Step 78: 52822 + 686 = 53508
Step 79: 53508 + 686 = 54194
Step 80: 54194 + 686 = 54880
Step 81: 54880 + 686 = 55566
Step 82: 55566 + 686 = 56252
Step 83: 56252 + 686 = 56938
Step 84: 56938 + 686 = 57624
Step 85: 57624 + 686 = 58310
Step 86: 58310 + 686 = 58996
Step 87: 58996 + 686 = 59682
Step 88: 59682 + 686 = 60368
Step 89: 60368 + 686 = 61054
Step 90: 61054 + 686 = 61740
Step 91: 61740 + 686 = 62426
Step 92: 62426 + 686 = 63112
Step 93: 63112 + 686 = 63798
Step 94: 63798 + 686 = 64484
Step 95: 64484 + 686 = 65170
Step 96: 65170 + 686 = 65856
Step 97: 65856 + 686 = 66542
Step 98: 66542 + 686 = 67228
Step 99: 67228 + 686 = 67914
Step 100: 67914 + 686 = 68600
Step 101: 68600 + 686 = 69286
Step 102: 69286 + 686 = 69972
Step 103: 69972 + 686 = 70658
Step 104: 70658 + 686 = 71344
Step 105: 71344 + 686 = 72030

So, 686*105 = 72030