Let's roll up our sleeves and solve this. We have 373 and we're going to multiply it by 420, essentially adding 373 to itself 420 times.
Step 1: 0 + 373 = 373
Step 2: 373 + 373 = 746
Step 3: 746 + 373 = 1119
Step 4: 1119 + 373 = 1492
Step 5: 1492 + 373 = 1865
Step 6: 1865 + 373 = 2238
Step 7: 2238 + 373 = 2611
Step 8: 2611 + 373 = 2984
Step 9: 2984 + 373 = 3357
Step 10: 3357 + 373 = 3730
Step 11: 3730 + 373 = 4103
Step 12: 4103 + 373 = 4476
Step 13: 4476 + 373 = 4849
Step 14: 4849 + 373 = 5222
Step 15: 5222 + 373 = 5595
Step 16: 5595 + 373 = 5968
Step 17: 5968 + 373 = 6341
Step 18: 6341 + 373 = 6714
Step 19: 6714 + 373 = 7087
Step 20: 7087 + 373 = 7460
Step 21: 7460 + 373 = 7833
Step 22: 7833 + 373 = 8206
Step 23: 8206 + 373 = 8579
Step 24: 8579 + 373 = 8952
Step 25: 8952 + 373 = 9325
Step 26: 9325 + 373 = 9698
Step 27: 9698 + 373 = 10071
Step 28: 10071 + 373 = 10444
Step 29: 10444 + 373 = 10817
Step 30: 10817 + 373 = 11190
Step 31: 11190 + 373 = 11563
Step 32: 11563 + 373 = 11936
Step 33: 11936 + 373 = 12309
Step 34: 12309 + 373 = 12682
Step 35: 12682 + 373 = 13055
Step 36: 13055 + 373 = 13428
Step 37: 13428 + 373 = 13801
Step 38: 13801 + 373 = 14174
Step 39: 14174 + 373 = 14547
Step 40: 14547 + 373 = 14920
Step 41: 14920 + 373 = 15293
Step 42: 15293 + 373 = 15666
Step 43: 15666 + 373 = 16039
Step 44: 16039 + 373 = 16412
Step 45: 16412 + 373 = 16785
Step 46: 16785 + 373 = 17158
Step 47: 17158 + 373 = 17531
Step 48: 17531 + 373 = 17904
Step 49: 17904 + 373 = 18277
Step 50: 18277 + 373 = 18650
Step 51: 18650 + 373 = 19023
Step 52: 19023 + 373 = 19396
Step 53: 19396 + 373 = 19769
Step 54: 19769 + 373 = 20142
Step 55: 20142 + 373 = 20515
Step 56: 20515 + 373 = 20888
Step 57: 20888 + 373 = 21261
Step 58: 21261 + 373 = 21634
Step 59: 21634 + 373 = 22007
Step 60: 22007 + 373 = 22380
Step 61: 22380 + 373 = 22753
Step 62: 22753 + 373 = 23126
Step 63: 23126 + 373 = 23499
Step 64: 23499 + 373 = 23872
Step 65: 23872 + 373 = 24245
Step 66: 24245 + 373 = 24618
Step 67: 24618 + 373 = 24991
Step 68: 24991 + 373 = 25364
Step 69: 25364 + 373 = 25737
Step 70: 25737 + 373 = 26110
Step 71: 26110 + 373 = 26483
Step 72: 26483 + 373 = 26856
Step 73: 26856 + 373 = 27229
Step 74: 27229 + 373 = 27602
Step 75: 27602 + 373 = 27975
Step 76: 27975 + 373 = 28348
Step 77: 28348 + 373 = 28721
Step 78: 28721 + 373 = 29094
Step 79: 29094 + 373 = 29467
Step 80: 29467 + 373 = 29840
Step 81: 29840 + 373 = 30213
Step 82: 30213 + 373 = 30586
Step 83: 30586 + 373 = 30959
Step 84: 30959 + 373 = 31332
Step 85: 31332 + 373 = 31705
Step 86: 31705 + 373 = 32078
Step 87: 32078 + 373 = 32451
Step 88: 32451 + 373 = 32824
Step 89: 32824 + 373 = 33197
Step 90: 33197 + 373 = 33570
Step 91: 33570 + 373 = 33943
Step 92: 33943 + 373 = 34316
Step 93: 34316 + 373 = 34689
Step 94: 34689 + 373 = 35062
Step 95: 35062 + 373 = 35435
Step 96: 35435 + 373 = 35808
Step 97: 35808 + 373 = 36181
Step 98: 36181 + 373 = 36554
Step 99: 36554 + 373 = 36927
Step 100: 36927 + 373 = 37300
Step 101: 37300 + 373 = 37673
Step 102: 37673 + 373 = 38046
Step 103: 38046 + 373 = 38419
Step 104: 38419 + 373 = 38792
Step 105: 38792 + 373 = 39165
Step 106: 39165 + 373 = 39538
Step 107: 39538 + 373 = 39911
Step 108: 39911 + 373 = 40284
Step 109: 40284 + 373 = 40657
Step 110: 40657 + 373 = 41030
Step 111: 41030 + 373 = 41403
Step 112: 41403 + 373 = 41776
Step 113: 41776 + 373 = 42149
Step 114: 42149 + 373 = 42522
Step 115: 42522 + 373 = 42895
Step 116: 42895 + 373 = 43268
Step 117: 43268 + 373 = 43641
Step 118: 43641 + 373 = 44014
Step 119: 44014 + 373 = 44387
Step 120: 44387 + 373 = 44760
Step 121: 44760 + 373 = 45133
Step 122: 45133 + 373 = 45506
Step 123: 45506 + 373 = 45879
Step 124: 45879 + 373 = 46252
Step 125: 46252 + 373 = 46625
Step 126: 46625 + 373 = 46998
Step 127: 46998 + 373 = 47371
Step 128: 47371 + 373 = 47744
Step 129: 47744 + 373 = 48117
Step 130: 48117 + 373 = 48490
Step 131: 48490 + 373 = 48863
Step 132: 48863 + 373 = 49236
Step 133: 49236 + 373 = 49609
Step 134: 49609 + 373 = 49982
Step 135: 49982 + 373 = 50355
Step 136: 50355 + 373 = 50728
Step 137: 50728 + 373 = 51101
Step 138: 51101 + 373 = 51474
Step 139: 51474 + 373 = 51847
Step 140: 51847 + 373 = 52220
Step 141: 52220 + 373 = 52593
Step 142: 52593 + 373 = 52966
Step 143: 52966 + 373 = 53339
Step 144: 53339 + 373 = 53712
Step 145: 53712 + 373 = 54085
Step 146: 54085 + 373 = 54458
Step 147: 54458 + 373 = 54831
Step 148: 54831 + 373 = 55204
Step 149: 55204 + 373 = 55577
Step 150: 55577 + 373 = 55950
Step 151: 55950 + 373 = 56323
Step 152: 56323 + 373 = 56696
Step 153: 56696 + 373 = 57069
Step 154: 57069 + 373 = 57442
Step 155: 57442 + 373 = 57815
Step 156: 57815 + 373 = 58188
Step 157: 58188 + 373 = 58561
Step 158: 58561 + 373 = 58934
Step 159: 58934 + 373 = 59307
Step 160: 59307 + 373 = 59680
Step 161: 59680 + 373 = 60053
Step 162: 60053 + 373 = 60426
Step 163: 60426 + 373 = 60799
Step 164: 60799 + 373 = 61172
Step 165: 61172 + 373 = 61545
Step 166: 61545 + 373 = 61918
Step 167: 61918 + 373 = 62291
Step 168: 62291 + 373 = 62664
Step 169: 62664 + 373 = 63037
Step 170: 63037 + 373 = 63410
Step 171: 63410 + 373 = 63783
Step 172: 63783 + 373 = 64156
Step 173: 64156 + 373 = 64529
Step 174: 64529 + 373 = 64902
Step 175: 64902 + 373 = 65275
Step 176: 65275 + 373 = 65648
Step 177: 65648 + 373 = 66021
Step 178: 66021 + 373 = 66394
Step 179: 66394 + 373 = 66767
Step 180: 66767 + 373 = 67140
Step 181: 67140 + 373 = 67513
Step 182: 67513 + 373 = 67886
Step 183: 67886 + 373 = 68259
Step 184: 68259 + 373 = 68632
Step 185: 68632 + 373 = 69005
Step 186: 69005 + 373 = 69378
Step 187: 69378 + 373 = 69751
Step 188: 69751 + 373 = 70124
Step 189: 70124 + 373 = 70497
Step 190: 70497 + 373 = 70870
Step 191: 70870 + 373 = 71243
Step 192: 71243 + 373 = 71616
Step 193: 71616 + 373 = 71989
Step 194: 71989 + 373 = 72362
Step 195: 72362 + 373 = 72735
Step 196: 72735 + 373 = 73108
Step 197: 73108 + 373 = 73481
Step 198: 73481 + 373 = 73854
Step 199: 73854 + 373 = 74227
Step 200: 74227 + 373 = 74600
Step 201: 74600 + 373 = 74973
Step 202: 74973 + 373 = 75346
Step 203: 75346 + 373 = 75719
Step 204: 75719 + 373 = 76092
Step 205: 76092 + 373 = 76465
Step 206: 76465 + 373 = 76838
Step 207: 76838 + 373 = 77211
Step 208: 77211 + 373 = 77584
Step 209: 77584 + 373 = 77957
Step 210: 77957 + 373 = 78330
Step 211: 78330 + 373 = 78703
Step 212: 78703 + 373 = 79076
Step 213: 79076 + 373 = 79449
Step 214: 79449 + 373 = 79822
Step 215: 79822 + 373 = 80195
Step 216: 80195 + 373 = 80568
Step 217: 80568 + 373 = 80941
Step 218: 80941 + 373 = 81314
Step 219: 81314 + 373 = 81687
Step 220: 81687 + 373 = 82060
Step 221: 82060 + 373 = 82433
Step 222: 82433 + 373 = 82806
Step 223: 82806 + 373 = 83179
Step 224: 83179 + 373 = 83552
Step 225: 83552 + 373 = 83925
Step 226: 83925 + 373 = 84298
Step 227: 84298 + 373 = 84671
Step 228: 84671 + 373 = 85044
Step 229: 85044 + 373 = 85417
Step 230: 85417 + 373 = 85790
Step 231: 85790 + 373 = 86163
Step 232: 86163 + 373 = 86536
Step 233: 86536 + 373 = 86909
Step 234: 86909 + 373 = 87282
Step 235: 87282 + 373 = 87655
Step 236: 87655 + 373 = 88028
Step 237: 88028 + 373 = 88401
Step 238: 88401 + 373 = 88774
Step 239: 88774 + 373 = 89147
Step 240: 89147 + 373 = 89520
Step 241: 89520 + 373 = 89893
Step 242: 89893 + 373 = 90266
Step 243: 90266 + 373 = 90639
Step 244: 90639 + 373 = 91012
Step 245: 91012 + 373 = 91385
Step 246: 91385 + 373 = 91758
Step 247: 91758 + 373 = 92131
Step 248: 92131 + 373 = 92504
Step 249: 92504 + 373 = 92877
Step 250: 92877 + 373 = 93250
Step 251: 93250 + 373 = 93623
Step 252: 93623 + 373 = 93996
Step 253: 93996 + 373 = 94369
Step 254: 94369 + 373 = 94742
Step 255: 94742 + 373 = 95115
Step 256: 95115 + 373 = 95488
Step 257: 95488 + 373 = 95861
Step 258: 95861 + 373 = 96234
Step 259: 96234 + 373 = 96607
Step 260: 96607 + 373 = 96980
Step 261: 96980 + 373 = 97353
Step 262: 97353 + 373 = 97726
Step 263: 97726 + 373 = 98099
Step 264: 98099 + 373 = 98472
Step 265: 98472 + 373 = 98845
Step 266: 98845 + 373 = 99218
Step 267: 99218 + 373 = 99591
Step 268: 99591 + 373 = 99964
Step 269: 99964 + 373 = 100337
Step 270: 100337 + 373 = 100710
Step 271: 100710 + 373 = 101083
Step 272: 101083 + 373 = 101456
Step 273: 101456 + 373 = 101829
Step 274: 101829 + 373 = 102202
Step 275: 102202 + 373 = 102575
Step 276: 102575 + 373 = 102948
Step 277: 102948 + 373 = 103321
Step 278: 103321 + 373 = 103694
Step 279: 103694 + 373 = 104067
Step 280: 104067 + 373 = 104440
Step 281: 104440 + 373 = 104813
Step 282: 104813 + 373 = 105186
Step 283: 105186 + 373 = 105559
Step 284: 105559 + 373 = 105932
Step 285: 105932 + 373 = 106305
Step 286: 106305 + 373 = 106678
Step 287: 106678 + 373 = 107051
Step 288: 107051 + 373 = 107424
Step 289: 107424 + 373 = 107797
Step 290: 107797 + 373 = 108170
Step 291: 108170 + 373 = 108543
Step 292: 108543 + 373 = 108916
Step 293: 108916 + 373 = 109289
Step 294: 109289 + 373 = 109662
Step 295: 109662 + 373 = 110035
Step 296: 110035 + 373 = 110408
Step 297: 110408 + 373 = 110781
Step 298: 110781 + 373 = 111154
Step 299: 111154 + 373 = 111527
Step 300: 111527 + 373 = 111900
Step 301: 111900 + 373 = 112273
Step 302: 112273 + 373 = 112646
Step 303: 112646 + 373 = 113019
Step 304: 113019 + 373 = 113392
Step 305: 113392 + 373 = 113765
Step 306: 113765 + 373 = 114138
Step 307: 114138 + 373 = 114511
Step 308: 114511 + 373 = 114884
Step 309: 114884 + 373 = 115257
Step 310: 115257 + 373 = 115630
Step 311: 115630 + 373 = 116003
Step 312: 116003 + 373 = 116376
Step 313: 116376 + 373 = 116749
Step 314: 116749 + 373 = 117122
Step 315: 117122 + 373 = 117495
Step 316: 117495 + 373 = 117868
Step 317: 117868 + 373 = 118241
Step 318: 118241 + 373 = 118614
Step 319: 118614 + 373 = 118987
Step 320: 118987 + 373 = 119360
Step 321: 119360 + 373 = 119733
Step 322: 119733 + 373 = 120106
Step 323: 120106 + 373 = 120479
Step 324: 120479 + 373 = 120852
Step 325: 120852 + 373 = 121225
Step 326: 121225 + 373 = 121598
Step 327: 121598 + 373 = 121971
Step 328: 121971 + 373 = 122344
Step 329: 122344 + 373 = 122717
Step 330: 122717 + 373 = 123090
Step 331: 123090 + 373 = 123463
Step 332: 123463 + 373 = 123836
Step 333: 123836 + 373 = 124209
Step 334: 124209 + 373 = 124582
Step 335: 124582 + 373 = 124955
Step 336: 124955 + 373 = 125328
Step 337: 125328 + 373 = 125701
Step 338: 125701 + 373 = 126074
Step 339: 126074 + 373 = 126447
Step 340: 126447 + 373 = 126820
Step 341: 126820 + 373 = 127193
Step 342: 127193 + 373 = 127566
Step 343: 127566 + 373 = 127939
Step 344: 127939 + 373 = 128312
Step 345: 128312 + 373 = 128685
Step 346: 128685 + 373 = 129058
Step 347: 129058 + 373 = 129431
Step 348: 129431 + 373 = 129804
Step 349: 129804 + 373 = 130177
Step 350: 130177 + 373 = 130550
Step 351: 130550 + 373 = 130923
Step 352: 130923 + 373 = 131296
Step 353: 131296 + 373 = 131669
Step 354: 131669 + 373 = 132042
Step 355: 132042 + 373 = 132415
Step 356: 132415 + 373 = 132788
Step 357: 132788 + 373 = 133161
Step 358: 133161 + 373 = 133534
Step 359: 133534 + 373 = 133907
Step 360: 133907 + 373 = 134280
Step 361: 134280 + 373 = 134653
Step 362: 134653 + 373 = 135026
Step 363: 135026 + 373 = 135399
Step 364: 135399 + 373 = 135772
Step 365: 135772 + 373 = 136145
Step 366: 136145 + 373 = 136518
Step 367: 136518 + 373 = 136891
Step 368: 136891 + 373 = 137264
Step 369: 137264 + 373 = 137637
Step 370: 137637 + 373 = 138010
Step 371: 138010 + 373 = 138383
Step 372: 138383 + 373 = 138756
Step 373: 138756 + 373 = 139129
Step 374: 139129 + 373 = 139502
Step 375: 139502 + 373 = 139875
Step 376: 139875 + 373 = 140248
Step 377: 140248 + 373 = 140621
Step 378: 140621 + 373 = 140994
Step 379: 140994 + 373 = 141367
Step 380: 141367 + 373 = 141740
Step 381: 141740 + 373 = 142113
Step 382: 142113 + 373 = 142486
Step 383: 142486 + 373 = 142859
Step 384: 142859 + 373 = 143232
Step 385: 143232 + 373 = 143605
Step 386: 143605 + 373 = 143978
Step 387: 143978 + 373 = 144351
Step 388: 144351 + 373 = 144724
Step 389: 144724 + 373 = 145097
Step 390: 145097 + 373 = 145470
Step 391: 145470 + 373 = 145843
Step 392: 145843 + 373 = 146216
Step 393: 146216 + 373 = 146589
Step 394: 146589 + 373 = 146962
Step 395: 146962 + 373 = 147335
Step 396: 147335 + 373 = 147708
Step 397: 147708 + 373 = 148081
Step 398: 148081 + 373 = 148454
Step 399: 148454 + 373 = 148827
Step 400: 148827 + 373 = 149200
Step 401: 149200 + 373 = 149573
Step 402: 149573 + 373 = 149946
Step 403: 149946 + 373 = 150319
Step 404: 150319 + 373 = 150692
Step 405: 150692 + 373 = 151065
Step 406: 151065 + 373 = 151438
Step 407: 151438 + 373 = 151811
Step 408: 151811 + 373 = 152184
Step 409: 152184 + 373 = 152557
Step 410: 152557 + 373 = 152930
Step 411: 152930 + 373 = 153303
Step 412: 153303 + 373 = 153676
Step 413: 153676 + 373 = 154049
Step 414: 154049 + 373 = 154422
Step 415: 154422 + 373 = 154795
Step 416: 154795 + 373 = 155168
Step 417: 155168 + 373 = 155541
Step 418: 155541 + 373 = 155914
Step 419: 155914 + 373 = 156287
Step 420: 156287 + 373 = 156660

So, 373*420 = 156660