OK, let's crack this. We're given 71 and our task is to multiply it by 129. Essentially, we'll be adding 71 to itself 129 times.
Step 1: 0 + 71 = 71
Step 2: 71 + 71 = 142
Step 3: 142 + 71 = 213
Step 4: 213 + 71 = 284
Step 5: 284 + 71 = 355
Step 6: 355 + 71 = 426
Step 7: 426 + 71 = 497
Step 8: 497 + 71 = 568
Step 9: 568 + 71 = 639
Step 10: 639 + 71 = 710
Step 11: 710 + 71 = 781
Step 12: 781 + 71 = 852
Step 13: 852 + 71 = 923
Step 14: 923 + 71 = 994
Step 15: 994 + 71 = 1065
Step 16: 1065 + 71 = 1136
Step 17: 1136 + 71 = 1207
Step 18: 1207 + 71 = 1278
Step 19: 1278 + 71 = 1349
Step 20: 1349 + 71 = 1420
Step 21: 1420 + 71 = 1491
Step 22: 1491 + 71 = 1562
Step 23: 1562 + 71 = 1633
Step 24: 1633 + 71 = 1704
Step 25: 1704 + 71 = 1775
Step 26: 1775 + 71 = 1846
Step 27: 1846 + 71 = 1917
Step 28: 1917 + 71 = 1988
Step 29: 1988 + 71 = 2059
Step 30: 2059 + 71 = 2130
Step 31: 2130 + 71 = 2201
Step 32: 2201 + 71 = 2272
Step 33: 2272 + 71 = 2343
Step 34: 2343 + 71 = 2414
Step 35: 2414 + 71 = 2485
Step 36: 2485 + 71 = 2556
Step 37: 2556 + 71 = 2627
Step 38: 2627 + 71 = 2698
Step 39: 2698 + 71 = 2769
Step 40: 2769 + 71 = 2840
Step 41: 2840 + 71 = 2911
Step 42: 2911 + 71 = 2982
Step 43: 2982 + 71 = 3053
Step 44: 3053 + 71 = 3124
Step 45: 3124 + 71 = 3195
Step 46: 3195 + 71 = 3266
Step 47: 3266 + 71 = 3337
Step 48: 3337 + 71 = 3408
Step 49: 3408 + 71 = 3479
Step 50: 3479 + 71 = 3550
Step 51: 3550 + 71 = 3621
Step 52: 3621 + 71 = 3692
Step 53: 3692 + 71 = 3763
Step 54: 3763 + 71 = 3834
Step 55: 3834 + 71 = 3905
Step 56: 3905 + 71 = 3976
Step 57: 3976 + 71 = 4047
Step 58: 4047 + 71 = 4118
Step 59: 4118 + 71 = 4189
Step 60: 4189 + 71 = 4260
Step 61: 4260 + 71 = 4331
Step 62: 4331 + 71 = 4402
Step 63: 4402 + 71 = 4473
Step 64: 4473 + 71 = 4544
Step 65: 4544 + 71 = 4615
Step 66: 4615 + 71 = 4686
Step 67: 4686 + 71 = 4757
Step 68: 4757 + 71 = 4828
Step 69: 4828 + 71 = 4899
Step 70: 4899 + 71 = 4970
Step 71: 4970 + 71 = 5041
Step 72: 5041 + 71 = 5112
Step 73: 5112 + 71 = 5183
Step 74: 5183 + 71 = 5254
Step 75: 5254 + 71 = 5325
Step 76: 5325 + 71 = 5396
Step 77: 5396 + 71 = 5467
Step 78: 5467 + 71 = 5538
Step 79: 5538 + 71 = 5609
Step 80: 5609 + 71 = 5680
Step 81: 5680 + 71 = 5751
Step 82: 5751 + 71 = 5822
Step 83: 5822 + 71 = 5893
Step 84: 5893 + 71 = 5964
Step 85: 5964 + 71 = 6035
Step 86: 6035 + 71 = 6106
Step 87: 6106 + 71 = 6177
Step 88: 6177 + 71 = 6248
Step 89: 6248 + 71 = 6319
Step 90: 6319 + 71 = 6390
Step 91: 6390 + 71 = 6461
Step 92: 6461 + 71 = 6532
Step 93: 6532 + 71 = 6603
Step 94: 6603 + 71 = 6674
Step 95: 6674 + 71 = 6745
Step 96: 6745 + 71 = 6816
Step 97: 6816 + 71 = 6887
Step 98: 6887 + 71 = 6958
Step 99: 6958 + 71 = 7029
Step 100: 7029 + 71 = 7100
Step 101: 7100 + 71 = 7171
Step 102: 7171 + 71 = 7242
Step 103: 7242 + 71 = 7313
Step 104: 7313 + 71 = 7384
Step 105: 7384 + 71 = 7455
Step 106: 7455 + 71 = 7526
Step 107: 7526 + 71 = 7597
Step 108: 7597 + 71 = 7668
Step 109: 7668 + 71 = 7739
Step 110: 7739 + 71 = 7810
Step 111: 7810 + 71 = 7881
Step 112: 7881 + 71 = 7952
Step 113: 7952 + 71 = 8023
Step 114: 8023 + 71 = 8094
Step 115: 8094 + 71 = 8165
Step 116: 8165 + 71 = 8236
Step 117: 8236 + 71 = 8307
Step 118: 8307 + 71 = 8378
Step 119: 8378 + 71 = 8449
Step 120: 8449 + 71 = 8520
Step 121: 8520 + 71 = 8591
Step 122: 8591 + 71 = 8662
Step 123: 8662 + 71 = 8733
Step 124: 8733 + 71 = 8804
Step 125: 8804 + 71 = 8875
Step 126: 8875 + 71 = 8946
Step 127: 8946 + 71 = 9017
Step 128: 9017 + 71 = 9088
Step 129: 9088 + 71 = 9159

So, 71*129 = 9159