Sure thing, let's get straight to it. We start with 551 and we're going to multiply it by 126, which means adding 551 to itself 126 times.
Step 1: 0 + 551 = 551
Step 2: 551 + 551 = 1102
Step 3: 1102 + 551 = 1653
Step 4: 1653 + 551 = 2204
Step 5: 2204 + 551 = 2755
Step 6: 2755 + 551 = 3306
Step 7: 3306 + 551 = 3857
Step 8: 3857 + 551 = 4408
Step 9: 4408 + 551 = 4959
Step 10: 4959 + 551 = 5510
Step 11: 5510 + 551 = 6061
Step 12: 6061 + 551 = 6612
Step 13: 6612 + 551 = 7163
Step 14: 7163 + 551 = 7714
Step 15: 7714 + 551 = 8265
Step 16: 8265 + 551 = 8816
Step 17: 8816 + 551 = 9367
Step 18: 9367 + 551 = 9918
Step 19: 9918 + 551 = 10469
Step 20: 10469 + 551 = 11020
Step 21: 11020 + 551 = 11571
Step 22: 11571 + 551 = 12122
Step 23: 12122 + 551 = 12673
Step 24: 12673 + 551 = 13224
Step 25: 13224 + 551 = 13775
Step 26: 13775 + 551 = 14326
Step 27: 14326 + 551 = 14877
Step 28: 14877 + 551 = 15428
Step 29: 15428 + 551 = 15979
Step 30: 15979 + 551 = 16530
Step 31: 16530 + 551 = 17081
Step 32: 17081 + 551 = 17632
Step 33: 17632 + 551 = 18183
Step 34: 18183 + 551 = 18734
Step 35: 18734 + 551 = 19285
Step 36: 19285 + 551 = 19836
Step 37: 19836 + 551 = 20387
Step 38: 20387 + 551 = 20938
Step 39: 20938 + 551 = 21489
Step 40: 21489 + 551 = 22040
Step 41: 22040 + 551 = 22591
Step 42: 22591 + 551 = 23142
Step 43: 23142 + 551 = 23693
Step 44: 23693 + 551 = 24244
Step 45: 24244 + 551 = 24795
Step 46: 24795 + 551 = 25346
Step 47: 25346 + 551 = 25897
Step 48: 25897 + 551 = 26448
Step 49: 26448 + 551 = 26999
Step 50: 26999 + 551 = 27550
Step 51: 27550 + 551 = 28101
Step 52: 28101 + 551 = 28652
Step 53: 28652 + 551 = 29203
Step 54: 29203 + 551 = 29754
Step 55: 29754 + 551 = 30305
Step 56: 30305 + 551 = 30856
Step 57: 30856 + 551 = 31407
Step 58: 31407 + 551 = 31958
Step 59: 31958 + 551 = 32509
Step 60: 32509 + 551 = 33060
Step 61: 33060 + 551 = 33611
Step 62: 33611 + 551 = 34162
Step 63: 34162 + 551 = 34713
Step 64: 34713 + 551 = 35264
Step 65: 35264 + 551 = 35815
Step 66: 35815 + 551 = 36366
Step 67: 36366 + 551 = 36917
Step 68: 36917 + 551 = 37468
Step 69: 37468 + 551 = 38019
Step 70: 38019 + 551 = 38570
Step 71: 38570 + 551 = 39121
Step 72: 39121 + 551 = 39672
Step 73: 39672 + 551 = 40223
Step 74: 40223 + 551 = 40774
Step 75: 40774 + 551 = 41325
Step 76: 41325 + 551 = 41876
Step 77: 41876 + 551 = 42427
Step 78: 42427 + 551 = 42978
Step 79: 42978 + 551 = 43529
Step 80: 43529 + 551 = 44080
Step 81: 44080 + 551 = 44631
Step 82: 44631 + 551 = 45182
Step 83: 45182 + 551 = 45733
Step 84: 45733 + 551 = 46284
Step 85: 46284 + 551 = 46835
Step 86: 46835 + 551 = 47386
Step 87: 47386 + 551 = 47937
Step 88: 47937 + 551 = 48488
Step 89: 48488 + 551 = 49039
Step 90: 49039 + 551 = 49590
Step 91: 49590 + 551 = 50141
Step 92: 50141 + 551 = 50692
Step 93: 50692 + 551 = 51243
Step 94: 51243 + 551 = 51794
Step 95: 51794 + 551 = 52345
Step 96: 52345 + 551 = 52896
Step 97: 52896 + 551 = 53447
Step 98: 53447 + 551 = 53998
Step 99: 53998 + 551 = 54549
Step 100: 54549 + 551 = 55100
Step 101: 55100 + 551 = 55651
Step 102: 55651 + 551 = 56202
Step 103: 56202 + 551 = 56753
Step 104: 56753 + 551 = 57304
Step 105: 57304 + 551 = 57855
Step 106: 57855 + 551 = 58406
Step 107: 58406 + 551 = 58957
Step 108: 58957 + 551 = 59508
Step 109: 59508 + 551 = 60059
Step 110: 60059 + 551 = 60610
Step 111: 60610 + 551 = 61161
Step 112: 61161 + 551 = 61712
Step 113: 61712 + 551 = 62263
Step 114: 62263 + 551 = 62814
Step 115: 62814 + 551 = 63365
Step 116: 63365 + 551 = 63916
Step 117: 63916 + 551 = 64467
Step 118: 64467 + 551 = 65018
Step 119: 65018 + 551 = 65569
Step 120: 65569 + 551 = 66120
Step 121: 66120 + 551 = 66671
Step 122: 66671 + 551 = 67222
Step 123: 67222 + 551 = 67773
Step 124: 67773 + 551 = 68324
Step 125: 68324 + 551 = 68875
Step 126: 68875 + 551 = 69426

So, 551*126 = 69426