OK, let's crack this. We're given 131 and our task is to multiply it by 166. Essentially, we'll be adding 131 to itself 166 times.
Step 1: 0 + 131 = 131
Step 2: 131 + 131 = 262
Step 3: 262 + 131 = 393
Step 4: 393 + 131 = 524
Step 5: 524 + 131 = 655
Step 6: 655 + 131 = 786
Step 7: 786 + 131 = 917
Step 8: 917 + 131 = 1048
Step 9: 1048 + 131 = 1179
Step 10: 1179 + 131 = 1310
Step 11: 1310 + 131 = 1441
Step 12: 1441 + 131 = 1572
Step 13: 1572 + 131 = 1703
Step 14: 1703 + 131 = 1834
Step 15: 1834 + 131 = 1965
Step 16: 1965 + 131 = 2096
Step 17: 2096 + 131 = 2227
Step 18: 2227 + 131 = 2358
Step 19: 2358 + 131 = 2489
Step 20: 2489 + 131 = 2620
Step 21: 2620 + 131 = 2751
Step 22: 2751 + 131 = 2882
Step 23: 2882 + 131 = 3013
Step 24: 3013 + 131 = 3144
Step 25: 3144 + 131 = 3275
Step 26: 3275 + 131 = 3406
Step 27: 3406 + 131 = 3537
Step 28: 3537 + 131 = 3668
Step 29: 3668 + 131 = 3799
Step 30: 3799 + 131 = 3930
Step 31: 3930 + 131 = 4061
Step 32: 4061 + 131 = 4192
Step 33: 4192 + 131 = 4323
Step 34: 4323 + 131 = 4454
Step 35: 4454 + 131 = 4585
Step 36: 4585 + 131 = 4716
Step 37: 4716 + 131 = 4847
Step 38: 4847 + 131 = 4978
Step 39: 4978 + 131 = 5109
Step 40: 5109 + 131 = 5240
Step 41: 5240 + 131 = 5371
Step 42: 5371 + 131 = 5502
Step 43: 5502 + 131 = 5633
Step 44: 5633 + 131 = 5764
Step 45: 5764 + 131 = 5895
Step 46: 5895 + 131 = 6026
Step 47: 6026 + 131 = 6157
Step 48: 6157 + 131 = 6288
Step 49: 6288 + 131 = 6419
Step 50: 6419 + 131 = 6550
Step 51: 6550 + 131 = 6681
Step 52: 6681 + 131 = 6812
Step 53: 6812 + 131 = 6943
Step 54: 6943 + 131 = 7074
Step 55: 7074 + 131 = 7205
Step 56: 7205 + 131 = 7336
Step 57: 7336 + 131 = 7467
Step 58: 7467 + 131 = 7598
Step 59: 7598 + 131 = 7729
Step 60: 7729 + 131 = 7860
Step 61: 7860 + 131 = 7991
Step 62: 7991 + 131 = 8122
Step 63: 8122 + 131 = 8253
Step 64: 8253 + 131 = 8384
Step 65: 8384 + 131 = 8515
Step 66: 8515 + 131 = 8646
Step 67: 8646 + 131 = 8777
Step 68: 8777 + 131 = 8908
Step 69: 8908 + 131 = 9039
Step 70: 9039 + 131 = 9170
Step 71: 9170 + 131 = 9301
Step 72: 9301 + 131 = 9432
Step 73: 9432 + 131 = 9563
Step 74: 9563 + 131 = 9694
Step 75: 9694 + 131 = 9825
Step 76: 9825 + 131 = 9956
Step 77: 9956 + 131 = 10087
Step 78: 10087 + 131 = 10218
Step 79: 10218 + 131 = 10349
Step 80: 10349 + 131 = 10480
Step 81: 10480 + 131 = 10611
Step 82: 10611 + 131 = 10742
Step 83: 10742 + 131 = 10873
Step 84: 10873 + 131 = 11004
Step 85: 11004 + 131 = 11135
Step 86: 11135 + 131 = 11266
Step 87: 11266 + 131 = 11397
Step 88: 11397 + 131 = 11528
Step 89: 11528 + 131 = 11659
Step 90: 11659 + 131 = 11790
Step 91: 11790 + 131 = 11921
Step 92: 11921 + 131 = 12052
Step 93: 12052 + 131 = 12183
Step 94: 12183 + 131 = 12314
Step 95: 12314 + 131 = 12445
Step 96: 12445 + 131 = 12576
Step 97: 12576 + 131 = 12707
Step 98: 12707 + 131 = 12838
Step 99: 12838 + 131 = 12969
Step 100: 12969 + 131 = 13100
Step 101: 13100 + 131 = 13231
Step 102: 13231 + 131 = 13362
Step 103: 13362 + 131 = 13493
Step 104: 13493 + 131 = 13624
Step 105: 13624 + 131 = 13755
Step 106: 13755 + 131 = 13886
Step 107: 13886 + 131 = 14017
Step 108: 14017 + 131 = 14148
Step 109: 14148 + 131 = 14279
Step 110: 14279 + 131 = 14410
Step 111: 14410 + 131 = 14541
Step 112: 14541 + 131 = 14672
Step 113: 14672 + 131 = 14803
Step 114: 14803 + 131 = 14934
Step 115: 14934 + 131 = 15065
Step 116: 15065 + 131 = 15196
Step 117: 15196 + 131 = 15327
Step 118: 15327 + 131 = 15458
Step 119: 15458 + 131 = 15589
Step 120: 15589 + 131 = 15720
Step 121: 15720 + 131 = 15851
Step 122: 15851 + 131 = 15982
Step 123: 15982 + 131 = 16113
Step 124: 16113 + 131 = 16244
Step 125: 16244 + 131 = 16375
Step 126: 16375 + 131 = 16506
Step 127: 16506 + 131 = 16637
Step 128: 16637 + 131 = 16768
Step 129: 16768 + 131 = 16899
Step 130: 16899 + 131 = 17030
Step 131: 17030 + 131 = 17161
Step 132: 17161 + 131 = 17292
Step 133: 17292 + 131 = 17423
Step 134: 17423 + 131 = 17554
Step 135: 17554 + 131 = 17685
Step 136: 17685 + 131 = 17816
Step 137: 17816 + 131 = 17947
Step 138: 17947 + 131 = 18078
Step 139: 18078 + 131 = 18209
Step 140: 18209 + 131 = 18340
Step 141: 18340 + 131 = 18471
Step 142: 18471 + 131 = 18602
Step 143: 18602 + 131 = 18733
Step 144: 18733 + 131 = 18864
Step 145: 18864 + 131 = 18995
Step 146: 18995 + 131 = 19126
Step 147: 19126 + 131 = 19257
Step 148: 19257 + 131 = 19388
Step 149: 19388 + 131 = 19519
Step 150: 19519 + 131 = 19650
Step 151: 19650 + 131 = 19781
Step 152: 19781 + 131 = 19912
Step 153: 19912 + 131 = 20043
Step 154: 20043 + 131 = 20174
Step 155: 20174 + 131 = 20305
Step 156: 20305 + 131 = 20436
Step 157: 20436 + 131 = 20567
Step 158: 20567 + 131 = 20698
Step 159: 20698 + 131 = 20829
Step 160: 20829 + 131 = 20960
Step 161: 20960 + 131 = 21091
Step 162: 21091 + 131 = 21222
Step 163: 21222 + 131 = 21353
Step 164: 21353 + 131 = 21484
Step 165: 21484 + 131 = 21615
Step 166: 21615 + 131 = 21746

So, 131*166 = 21746