Let's roll up our sleeves and solve this. We have 147 and we're going to multiply it by 147, essentially adding 147 to itself 147 times.
Step 1: 0 + 147 = 147
Step 2: 147 + 147 = 294
Step 3: 294 + 147 = 441
Step 4: 441 + 147 = 588
Step 5: 588 + 147 = 735
Step 6: 735 + 147 = 882
Step 7: 882 + 147 = 1029
Step 8: 1029 + 147 = 1176
Step 9: 1176 + 147 = 1323
Step 10: 1323 + 147 = 1470
Step 11: 1470 + 147 = 1617
Step 12: 1617 + 147 = 1764
Step 13: 1764 + 147 = 1911
Step 14: 1911 + 147 = 2058
Step 15: 2058 + 147 = 2205
Step 16: 2205 + 147 = 2352
Step 17: 2352 + 147 = 2499
Step 18: 2499 + 147 = 2646
Step 19: 2646 + 147 = 2793
Step 20: 2793 + 147 = 2940
Step 21: 2940 + 147 = 3087
Step 22: 3087 + 147 = 3234
Step 23: 3234 + 147 = 3381
Step 24: 3381 + 147 = 3528
Step 25: 3528 + 147 = 3675
Step 26: 3675 + 147 = 3822
Step 27: 3822 + 147 = 3969
Step 28: 3969 + 147 = 4116
Step 29: 4116 + 147 = 4263
Step 30: 4263 + 147 = 4410
Step 31: 4410 + 147 = 4557
Step 32: 4557 + 147 = 4704
Step 33: 4704 + 147 = 4851
Step 34: 4851 + 147 = 4998
Step 35: 4998 + 147 = 5145
Step 36: 5145 + 147 = 5292
Step 37: 5292 + 147 = 5439
Step 38: 5439 + 147 = 5586
Step 39: 5586 + 147 = 5733
Step 40: 5733 + 147 = 5880
Step 41: 5880 + 147 = 6027
Step 42: 6027 + 147 = 6174
Step 43: 6174 + 147 = 6321
Step 44: 6321 + 147 = 6468
Step 45: 6468 + 147 = 6615
Step 46: 6615 + 147 = 6762
Step 47: 6762 + 147 = 6909
Step 48: 6909 + 147 = 7056
Step 49: 7056 + 147 = 7203
Step 50: 7203 + 147 = 7350
Step 51: 7350 + 147 = 7497
Step 52: 7497 + 147 = 7644
Step 53: 7644 + 147 = 7791
Step 54: 7791 + 147 = 7938
Step 55: 7938 + 147 = 8085
Step 56: 8085 + 147 = 8232
Step 57: 8232 + 147 = 8379
Step 58: 8379 + 147 = 8526
Step 59: 8526 + 147 = 8673
Step 60: 8673 + 147 = 8820
Step 61: 8820 + 147 = 8967
Step 62: 8967 + 147 = 9114
Step 63: 9114 + 147 = 9261
Step 64: 9261 + 147 = 9408
Step 65: 9408 + 147 = 9555
Step 66: 9555 + 147 = 9702
Step 67: 9702 + 147 = 9849
Step 68: 9849 + 147 = 9996
Step 69: 9996 + 147 = 10143
Step 70: 10143 + 147 = 10290
Step 71: 10290 + 147 = 10437
Step 72: 10437 + 147 = 10584
Step 73: 10584 + 147 = 10731
Step 74: 10731 + 147 = 10878
Step 75: 10878 + 147 = 11025
Step 76: 11025 + 147 = 11172
Step 77: 11172 + 147 = 11319
Step 78: 11319 + 147 = 11466
Step 79: 11466 + 147 = 11613
Step 80: 11613 + 147 = 11760
Step 81: 11760 + 147 = 11907
Step 82: 11907 + 147 = 12054
Step 83: 12054 + 147 = 12201
Step 84: 12201 + 147 = 12348
Step 85: 12348 + 147 = 12495
Step 86: 12495 + 147 = 12642
Step 87: 12642 + 147 = 12789
Step 88: 12789 + 147 = 12936
Step 89: 12936 + 147 = 13083
Step 90: 13083 + 147 = 13230
Step 91: 13230 + 147 = 13377
Step 92: 13377 + 147 = 13524
Step 93: 13524 + 147 = 13671
Step 94: 13671 + 147 = 13818
Step 95: 13818 + 147 = 13965
Step 96: 13965 + 147 = 14112
Step 97: 14112 + 147 = 14259
Step 98: 14259 + 147 = 14406
Step 99: 14406 + 147 = 14553
Step 100: 14553 + 147 = 14700
Step 101: 14700 + 147 = 14847
Step 102: 14847 + 147 = 14994
Step 103: 14994 + 147 = 15141
Step 104: 15141 + 147 = 15288
Step 105: 15288 + 147 = 15435
Step 106: 15435 + 147 = 15582
Step 107: 15582 + 147 = 15729
Step 108: 15729 + 147 = 15876
Step 109: 15876 + 147 = 16023
Step 110: 16023 + 147 = 16170
Step 111: 16170 + 147 = 16317
Step 112: 16317 + 147 = 16464
Step 113: 16464 + 147 = 16611
Step 114: 16611 + 147 = 16758
Step 115: 16758 + 147 = 16905
Step 116: 16905 + 147 = 17052
Step 117: 17052 + 147 = 17199
Step 118: 17199 + 147 = 17346
Step 119: 17346 + 147 = 17493
Step 120: 17493 + 147 = 17640
Step 121: 17640 + 147 = 17787
Step 122: 17787 + 147 = 17934
Step 123: 17934 + 147 = 18081
Step 124: 18081 + 147 = 18228
Step 125: 18228 + 147 = 18375
Step 126: 18375 + 147 = 18522
Step 127: 18522 + 147 = 18669
Step 128: 18669 + 147 = 18816
Step 129: 18816 + 147 = 18963
Step 130: 18963 + 147 = 19110
Step 131: 19110 + 147 = 19257
Step 132: 19257 + 147 = 19404
Step 133: 19404 + 147 = 19551
Step 134: 19551 + 147 = 19698
Step 135: 19698 + 147 = 19845
Step 136: 19845 + 147 = 19992
Step 137: 19992 + 147 = 20139
Step 138: 20139 + 147 = 20286
Step 139: 20286 + 147 = 20433
Step 140: 20433 + 147 = 20580
Step 141: 20580 + 147 = 20727
Step 142: 20727 + 147 = 20874
Step 143: 20874 + 147 = 21021
Step 144: 21021 + 147 = 21168
Step 145: 21168 + 147 = 21315
Step 146: 21315 + 147 = 21462
Step 147: 21462 + 147 = 21609

So, 147*147 = 21609