Let's roll up our sleeves and solve this. We have 423 and we're going to multiply it by 411, essentially adding 423 to itself 411 times.
Step 1: 0 + 423 = 423
Step 2: 423 + 423 = 846
Step 3: 846 + 423 = 1269
Step 4: 1269 + 423 = 1692
Step 5: 1692 + 423 = 2115
Step 6: 2115 + 423 = 2538
Step 7: 2538 + 423 = 2961
Step 8: 2961 + 423 = 3384
Step 9: 3384 + 423 = 3807
Step 10: 3807 + 423 = 4230
Step 11: 4230 + 423 = 4653
Step 12: 4653 + 423 = 5076
Step 13: 5076 + 423 = 5499
Step 14: 5499 + 423 = 5922
Step 15: 5922 + 423 = 6345
Step 16: 6345 + 423 = 6768
Step 17: 6768 + 423 = 7191
Step 18: 7191 + 423 = 7614
Step 19: 7614 + 423 = 8037
Step 20: 8037 + 423 = 8460
Step 21: 8460 + 423 = 8883
Step 22: 8883 + 423 = 9306
Step 23: 9306 + 423 = 9729
Step 24: 9729 + 423 = 10152
Step 25: 10152 + 423 = 10575
Step 26: 10575 + 423 = 10998
Step 27: 10998 + 423 = 11421
Step 28: 11421 + 423 = 11844
Step 29: 11844 + 423 = 12267
Step 30: 12267 + 423 = 12690
Step 31: 12690 + 423 = 13113
Step 32: 13113 + 423 = 13536
Step 33: 13536 + 423 = 13959
Step 34: 13959 + 423 = 14382
Step 35: 14382 + 423 = 14805
Step 36: 14805 + 423 = 15228
Step 37: 15228 + 423 = 15651
Step 38: 15651 + 423 = 16074
Step 39: 16074 + 423 = 16497
Step 40: 16497 + 423 = 16920
Step 41: 16920 + 423 = 17343
Step 42: 17343 + 423 = 17766
Step 43: 17766 + 423 = 18189
Step 44: 18189 + 423 = 18612
Step 45: 18612 + 423 = 19035
Step 46: 19035 + 423 = 19458
Step 47: 19458 + 423 = 19881
Step 48: 19881 + 423 = 20304
Step 49: 20304 + 423 = 20727
Step 50: 20727 + 423 = 21150
Step 51: 21150 + 423 = 21573
Step 52: 21573 + 423 = 21996
Step 53: 21996 + 423 = 22419
Step 54: 22419 + 423 = 22842
Step 55: 22842 + 423 = 23265
Step 56: 23265 + 423 = 23688
Step 57: 23688 + 423 = 24111
Step 58: 24111 + 423 = 24534
Step 59: 24534 + 423 = 24957
Step 60: 24957 + 423 = 25380
Step 61: 25380 + 423 = 25803
Step 62: 25803 + 423 = 26226
Step 63: 26226 + 423 = 26649
Step 64: 26649 + 423 = 27072
Step 65: 27072 + 423 = 27495
Step 66: 27495 + 423 = 27918
Step 67: 27918 + 423 = 28341
Step 68: 28341 + 423 = 28764
Step 69: 28764 + 423 = 29187
Step 70: 29187 + 423 = 29610
Step 71: 29610 + 423 = 30033
Step 72: 30033 + 423 = 30456
Step 73: 30456 + 423 = 30879
Step 74: 30879 + 423 = 31302
Step 75: 31302 + 423 = 31725
Step 76: 31725 + 423 = 32148
Step 77: 32148 + 423 = 32571
Step 78: 32571 + 423 = 32994
Step 79: 32994 + 423 = 33417
Step 80: 33417 + 423 = 33840
Step 81: 33840 + 423 = 34263
Step 82: 34263 + 423 = 34686
Step 83: 34686 + 423 = 35109
Step 84: 35109 + 423 = 35532
Step 85: 35532 + 423 = 35955
Step 86: 35955 + 423 = 36378
Step 87: 36378 + 423 = 36801
Step 88: 36801 + 423 = 37224
Step 89: 37224 + 423 = 37647
Step 90: 37647 + 423 = 38070
Step 91: 38070 + 423 = 38493
Step 92: 38493 + 423 = 38916
Step 93: 38916 + 423 = 39339
Step 94: 39339 + 423 = 39762
Step 95: 39762 + 423 = 40185
Step 96: 40185 + 423 = 40608
Step 97: 40608 + 423 = 41031
Step 98: 41031 + 423 = 41454
Step 99: 41454 + 423 = 41877
Step 100: 41877 + 423 = 42300
Step 101: 42300 + 423 = 42723
Step 102: 42723 + 423 = 43146
Step 103: 43146 + 423 = 43569
Step 104: 43569 + 423 = 43992
Step 105: 43992 + 423 = 44415
Step 106: 44415 + 423 = 44838
Step 107: 44838 + 423 = 45261
Step 108: 45261 + 423 = 45684
Step 109: 45684 + 423 = 46107
Step 110: 46107 + 423 = 46530
Step 111: 46530 + 423 = 46953
Step 112: 46953 + 423 = 47376
Step 113: 47376 + 423 = 47799
Step 114: 47799 + 423 = 48222
Step 115: 48222 + 423 = 48645
Step 116: 48645 + 423 = 49068
Step 117: 49068 + 423 = 49491
Step 118: 49491 + 423 = 49914
Step 119: 49914 + 423 = 50337
Step 120: 50337 + 423 = 50760
Step 121: 50760 + 423 = 51183
Step 122: 51183 + 423 = 51606
Step 123: 51606 + 423 = 52029
Step 124: 52029 + 423 = 52452
Step 125: 52452 + 423 = 52875
Step 126: 52875 + 423 = 53298
Step 127: 53298 + 423 = 53721
Step 128: 53721 + 423 = 54144
Step 129: 54144 + 423 = 54567
Step 130: 54567 + 423 = 54990
Step 131: 54990 + 423 = 55413
Step 132: 55413 + 423 = 55836
Step 133: 55836 + 423 = 56259
Step 134: 56259 + 423 = 56682
Step 135: 56682 + 423 = 57105
Step 136: 57105 + 423 = 57528
Step 137: 57528 + 423 = 57951
Step 138: 57951 + 423 = 58374
Step 139: 58374 + 423 = 58797
Step 140: 58797 + 423 = 59220
Step 141: 59220 + 423 = 59643
Step 142: 59643 + 423 = 60066
Step 143: 60066 + 423 = 60489
Step 144: 60489 + 423 = 60912
Step 145: 60912 + 423 = 61335
Step 146: 61335 + 423 = 61758
Step 147: 61758 + 423 = 62181
Step 148: 62181 + 423 = 62604
Step 149: 62604 + 423 = 63027
Step 150: 63027 + 423 = 63450
Step 151: 63450 + 423 = 63873
Step 152: 63873 + 423 = 64296
Step 153: 64296 + 423 = 64719
Step 154: 64719 + 423 = 65142
Step 155: 65142 + 423 = 65565
Step 156: 65565 + 423 = 65988
Step 157: 65988 + 423 = 66411
Step 158: 66411 + 423 = 66834
Step 159: 66834 + 423 = 67257
Step 160: 67257 + 423 = 67680
Step 161: 67680 + 423 = 68103
Step 162: 68103 + 423 = 68526
Step 163: 68526 + 423 = 68949
Step 164: 68949 + 423 = 69372
Step 165: 69372 + 423 = 69795
Step 166: 69795 + 423 = 70218
Step 167: 70218 + 423 = 70641
Step 168: 70641 + 423 = 71064
Step 169: 71064 + 423 = 71487
Step 170: 71487 + 423 = 71910
Step 171: 71910 + 423 = 72333
Step 172: 72333 + 423 = 72756
Step 173: 72756 + 423 = 73179
Step 174: 73179 + 423 = 73602
Step 175: 73602 + 423 = 74025
Step 176: 74025 + 423 = 74448
Step 177: 74448 + 423 = 74871
Step 178: 74871 + 423 = 75294
Step 179: 75294 + 423 = 75717
Step 180: 75717 + 423 = 76140
Step 181: 76140 + 423 = 76563
Step 182: 76563 + 423 = 76986
Step 183: 76986 + 423 = 77409
Step 184: 77409 + 423 = 77832
Step 185: 77832 + 423 = 78255
Step 186: 78255 + 423 = 78678
Step 187: 78678 + 423 = 79101
Step 188: 79101 + 423 = 79524
Step 189: 79524 + 423 = 79947
Step 190: 79947 + 423 = 80370
Step 191: 80370 + 423 = 80793
Step 192: 80793 + 423 = 81216
Step 193: 81216 + 423 = 81639
Step 194: 81639 + 423 = 82062
Step 195: 82062 + 423 = 82485
Step 196: 82485 + 423 = 82908
Step 197: 82908 + 423 = 83331
Step 198: 83331 + 423 = 83754
Step 199: 83754 + 423 = 84177
Step 200: 84177 + 423 = 84600
Step 201: 84600 + 423 = 85023
Step 202: 85023 + 423 = 85446
Step 203: 85446 + 423 = 85869
Step 204: 85869 + 423 = 86292
Step 205: 86292 + 423 = 86715
Step 206: 86715 + 423 = 87138
Step 207: 87138 + 423 = 87561
Step 208: 87561 + 423 = 87984
Step 209: 87984 + 423 = 88407
Step 210: 88407 + 423 = 88830
Step 211: 88830 + 423 = 89253
Step 212: 89253 + 423 = 89676
Step 213: 89676 + 423 = 90099
Step 214: 90099 + 423 = 90522
Step 215: 90522 + 423 = 90945
Step 216: 90945 + 423 = 91368
Step 217: 91368 + 423 = 91791
Step 218: 91791 + 423 = 92214
Step 219: 92214 + 423 = 92637
Step 220: 92637 + 423 = 93060
Step 221: 93060 + 423 = 93483
Step 222: 93483 + 423 = 93906
Step 223: 93906 + 423 = 94329
Step 224: 94329 + 423 = 94752
Step 225: 94752 + 423 = 95175
Step 226: 95175 + 423 = 95598
Step 227: 95598 + 423 = 96021
Step 228: 96021 + 423 = 96444
Step 229: 96444 + 423 = 96867
Step 230: 96867 + 423 = 97290
Step 231: 97290 + 423 = 97713
Step 232: 97713 + 423 = 98136
Step 233: 98136 + 423 = 98559
Step 234: 98559 + 423 = 98982
Step 235: 98982 + 423 = 99405
Step 236: 99405 + 423 = 99828
Step 237: 99828 + 423 = 100251
Step 238: 100251 + 423 = 100674
Step 239: 100674 + 423 = 101097
Step 240: 101097 + 423 = 101520
Step 241: 101520 + 423 = 101943
Step 242: 101943 + 423 = 102366
Step 243: 102366 + 423 = 102789
Step 244: 102789 + 423 = 103212
Step 245: 103212 + 423 = 103635
Step 246: 103635 + 423 = 104058
Step 247: 104058 + 423 = 104481
Step 248: 104481 + 423 = 104904
Step 249: 104904 + 423 = 105327
Step 250: 105327 + 423 = 105750
Step 251: 105750 + 423 = 106173
Step 252: 106173 + 423 = 106596
Step 253: 106596 + 423 = 107019
Step 254: 107019 + 423 = 107442
Step 255: 107442 + 423 = 107865
Step 256: 107865 + 423 = 108288
Step 257: 108288 + 423 = 108711
Step 258: 108711 + 423 = 109134
Step 259: 109134 + 423 = 109557
Step 260: 109557 + 423 = 109980
Step 261: 109980 + 423 = 110403
Step 262: 110403 + 423 = 110826
Step 263: 110826 + 423 = 111249
Step 264: 111249 + 423 = 111672
Step 265: 111672 + 423 = 112095
Step 266: 112095 + 423 = 112518
Step 267: 112518 + 423 = 112941
Step 268: 112941 + 423 = 113364
Step 269: 113364 + 423 = 113787
Step 270: 113787 + 423 = 114210
Step 271: 114210 + 423 = 114633
Step 272: 114633 + 423 = 115056
Step 273: 115056 + 423 = 115479
Step 274: 115479 + 423 = 115902
Step 275: 115902 + 423 = 116325
Step 276: 116325 + 423 = 116748
Step 277: 116748 + 423 = 117171
Step 278: 117171 + 423 = 117594
Step 279: 117594 + 423 = 118017
Step 280: 118017 + 423 = 118440
Step 281: 118440 + 423 = 118863
Step 282: 118863 + 423 = 119286
Step 283: 119286 + 423 = 119709
Step 284: 119709 + 423 = 120132
Step 285: 120132 + 423 = 120555
Step 286: 120555 + 423 = 120978
Step 287: 120978 + 423 = 121401
Step 288: 121401 + 423 = 121824
Step 289: 121824 + 423 = 122247
Step 290: 122247 + 423 = 122670
Step 291: 122670 + 423 = 123093
Step 292: 123093 + 423 = 123516
Step 293: 123516 + 423 = 123939
Step 294: 123939 + 423 = 124362
Step 295: 124362 + 423 = 124785
Step 296: 124785 + 423 = 125208
Step 297: 125208 + 423 = 125631
Step 298: 125631 + 423 = 126054
Step 299: 126054 + 423 = 126477
Step 300: 126477 + 423 = 126900
Step 301: 126900 + 423 = 127323
Step 302: 127323 + 423 = 127746
Step 303: 127746 + 423 = 128169
Step 304: 128169 + 423 = 128592
Step 305: 128592 + 423 = 129015
Step 306: 129015 + 423 = 129438
Step 307: 129438 + 423 = 129861
Step 308: 129861 + 423 = 130284
Step 309: 130284 + 423 = 130707
Step 310: 130707 + 423 = 131130
Step 311: 131130 + 423 = 131553
Step 312: 131553 + 423 = 131976
Step 313: 131976 + 423 = 132399
Step 314: 132399 + 423 = 132822
Step 315: 132822 + 423 = 133245
Step 316: 133245 + 423 = 133668
Step 317: 133668 + 423 = 134091
Step 318: 134091 + 423 = 134514
Step 319: 134514 + 423 = 134937
Step 320: 134937 + 423 = 135360
Step 321: 135360 + 423 = 135783
Step 322: 135783 + 423 = 136206
Step 323: 136206 + 423 = 136629
Step 324: 136629 + 423 = 137052
Step 325: 137052 + 423 = 137475
Step 326: 137475 + 423 = 137898
Step 327: 137898 + 423 = 138321
Step 328: 138321 + 423 = 138744
Step 329: 138744 + 423 = 139167
Step 330: 139167 + 423 = 139590
Step 331: 139590 + 423 = 140013
Step 332: 140013 + 423 = 140436
Step 333: 140436 + 423 = 140859
Step 334: 140859 + 423 = 141282
Step 335: 141282 + 423 = 141705
Step 336: 141705 + 423 = 142128
Step 337: 142128 + 423 = 142551
Step 338: 142551 + 423 = 142974
Step 339: 142974 + 423 = 143397
Step 340: 143397 + 423 = 143820
Step 341: 143820 + 423 = 144243
Step 342: 144243 + 423 = 144666
Step 343: 144666 + 423 = 145089
Step 344: 145089 + 423 = 145512
Step 345: 145512 + 423 = 145935
Step 346: 145935 + 423 = 146358
Step 347: 146358 + 423 = 146781
Step 348: 146781 + 423 = 147204
Step 349: 147204 + 423 = 147627
Step 350: 147627 + 423 = 148050
Step 351: 148050 + 423 = 148473
Step 352: 148473 + 423 = 148896
Step 353: 148896 + 423 = 149319
Step 354: 149319 + 423 = 149742
Step 355: 149742 + 423 = 150165
Step 356: 150165 + 423 = 150588
Step 357: 150588 + 423 = 151011
Step 358: 151011 + 423 = 151434
Step 359: 151434 + 423 = 151857
Step 360: 151857 + 423 = 152280
Step 361: 152280 + 423 = 152703
Step 362: 152703 + 423 = 153126
Step 363: 153126 + 423 = 153549
Step 364: 153549 + 423 = 153972
Step 365: 153972 + 423 = 154395
Step 366: 154395 + 423 = 154818
Step 367: 154818 + 423 = 155241
Step 368: 155241 + 423 = 155664
Step 369: 155664 + 423 = 156087
Step 370: 156087 + 423 = 156510
Step 371: 156510 + 423 = 156933
Step 372: 156933 + 423 = 157356
Step 373: 157356 + 423 = 157779
Step 374: 157779 + 423 = 158202
Step 375: 158202 + 423 = 158625
Step 376: 158625 + 423 = 159048
Step 377: 159048 + 423 = 159471
Step 378: 159471 + 423 = 159894
Step 379: 159894 + 423 = 160317
Step 380: 160317 + 423 = 160740
Step 381: 160740 + 423 = 161163
Step 382: 161163 + 423 = 161586
Step 383: 161586 + 423 = 162009
Step 384: 162009 + 423 = 162432
Step 385: 162432 + 423 = 162855
Step 386: 162855 + 423 = 163278
Step 387: 163278 + 423 = 163701
Step 388: 163701 + 423 = 164124
Step 389: 164124 + 423 = 164547
Step 390: 164547 + 423 = 164970
Step 391: 164970 + 423 = 165393
Step 392: 165393 + 423 = 165816
Step 393: 165816 + 423 = 166239
Step 394: 166239 + 423 = 166662
Step 395: 166662 + 423 = 167085
Step 396: 167085 + 423 = 167508
Step 397: 167508 + 423 = 167931
Step 398: 167931 + 423 = 168354
Step 399: 168354 + 423 = 168777
Step 400: 168777 + 423 = 169200
Step 401: 169200 + 423 = 169623
Step 402: 169623 + 423 = 170046
Step 403: 170046 + 423 = 170469
Step 404: 170469 + 423 = 170892
Step 405: 170892 + 423 = 171315
Step 406: 171315 + 423 = 171738
Step 407: 171738 + 423 = 172161
Step 408: 172161 + 423 = 172584
Step 409: 172584 + 423 = 173007
Step 410: 173007 + 423 = 173430
Step 411: 173430 + 423 = 173853

So, 423*411 = 173853