Alright, let's solve this math problem step by step. First, we have the number 406. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 423. So, we're going to take the number 406 and add it to itself 423 times.
Step 1: 0 + 406 = 406
Step 2: 406 + 406 = 812
Step 3: 812 + 406 = 1218
Step 4: 1218 + 406 = 1624
Step 5: 1624 + 406 = 2030
Step 6: 2030 + 406 = 2436
Step 7: 2436 + 406 = 2842
Step 8: 2842 + 406 = 3248
Step 9: 3248 + 406 = 3654
Step 10: 3654 + 406 = 4060
Step 11: 4060 + 406 = 4466
Step 12: 4466 + 406 = 4872
Step 13: 4872 + 406 = 5278
Step 14: 5278 + 406 = 5684
Step 15: 5684 + 406 = 6090
Step 16: 6090 + 406 = 6496
Step 17: 6496 + 406 = 6902
Step 18: 6902 + 406 = 7308
Step 19: 7308 + 406 = 7714
Step 20: 7714 + 406 = 8120
Step 21: 8120 + 406 = 8526
Step 22: 8526 + 406 = 8932
Step 23: 8932 + 406 = 9338
Step 24: 9338 + 406 = 9744
Step 25: 9744 + 406 = 10150
Step 26: 10150 + 406 = 10556
Step 27: 10556 + 406 = 10962
Step 28: 10962 + 406 = 11368
Step 29: 11368 + 406 = 11774
Step 30: 11774 + 406 = 12180
Step 31: 12180 + 406 = 12586
Step 32: 12586 + 406 = 12992
Step 33: 12992 + 406 = 13398
Step 34: 13398 + 406 = 13804
Step 35: 13804 + 406 = 14210
Step 36: 14210 + 406 = 14616
Step 37: 14616 + 406 = 15022
Step 38: 15022 + 406 = 15428
Step 39: 15428 + 406 = 15834
Step 40: 15834 + 406 = 16240
Step 41: 16240 + 406 = 16646
Step 42: 16646 + 406 = 17052
Step 43: 17052 + 406 = 17458
Step 44: 17458 + 406 = 17864
Step 45: 17864 + 406 = 18270
Step 46: 18270 + 406 = 18676
Step 47: 18676 + 406 = 19082
Step 48: 19082 + 406 = 19488
Step 49: 19488 + 406 = 19894
Step 50: 19894 + 406 = 20300
Step 51: 20300 + 406 = 20706
Step 52: 20706 + 406 = 21112
Step 53: 21112 + 406 = 21518
Step 54: 21518 + 406 = 21924
Step 55: 21924 + 406 = 22330
Step 56: 22330 + 406 = 22736
Step 57: 22736 + 406 = 23142
Step 58: 23142 + 406 = 23548
Step 59: 23548 + 406 = 23954
Step 60: 23954 + 406 = 24360
Step 61: 24360 + 406 = 24766
Step 62: 24766 + 406 = 25172
Step 63: 25172 + 406 = 25578
Step 64: 25578 + 406 = 25984
Step 65: 25984 + 406 = 26390
Step 66: 26390 + 406 = 26796
Step 67: 26796 + 406 = 27202
Step 68: 27202 + 406 = 27608
Step 69: 27608 + 406 = 28014
Step 70: 28014 + 406 = 28420
Step 71: 28420 + 406 = 28826
Step 72: 28826 + 406 = 29232
Step 73: 29232 + 406 = 29638
Step 74: 29638 + 406 = 30044
Step 75: 30044 + 406 = 30450
Step 76: 30450 + 406 = 30856
Step 77: 30856 + 406 = 31262
Step 78: 31262 + 406 = 31668
Step 79: 31668 + 406 = 32074
Step 80: 32074 + 406 = 32480
Step 81: 32480 + 406 = 32886
Step 82: 32886 + 406 = 33292
Step 83: 33292 + 406 = 33698
Step 84: 33698 + 406 = 34104
Step 85: 34104 + 406 = 34510
Step 86: 34510 + 406 = 34916
Step 87: 34916 + 406 = 35322
Step 88: 35322 + 406 = 35728
Step 89: 35728 + 406 = 36134
Step 90: 36134 + 406 = 36540
Step 91: 36540 + 406 = 36946
Step 92: 36946 + 406 = 37352
Step 93: 37352 + 406 = 37758
Step 94: 37758 + 406 = 38164
Step 95: 38164 + 406 = 38570
Step 96: 38570 + 406 = 38976
Step 97: 38976 + 406 = 39382
Step 98: 39382 + 406 = 39788
Step 99: 39788 + 406 = 40194
Step 100: 40194 + 406 = 40600
Step 101: 40600 + 406 = 41006
Step 102: 41006 + 406 = 41412
Step 103: 41412 + 406 = 41818
Step 104: 41818 + 406 = 42224
Step 105: 42224 + 406 = 42630
Step 106: 42630 + 406 = 43036
Step 107: 43036 + 406 = 43442
Step 108: 43442 + 406 = 43848
Step 109: 43848 + 406 = 44254
Step 110: 44254 + 406 = 44660
Step 111: 44660 + 406 = 45066
Step 112: 45066 + 406 = 45472
Step 113: 45472 + 406 = 45878
Step 114: 45878 + 406 = 46284
Step 115: 46284 + 406 = 46690
Step 116: 46690 + 406 = 47096
Step 117: 47096 + 406 = 47502
Step 118: 47502 + 406 = 47908
Step 119: 47908 + 406 = 48314
Step 120: 48314 + 406 = 48720
Step 121: 48720 + 406 = 49126
Step 122: 49126 + 406 = 49532
Step 123: 49532 + 406 = 49938
Step 124: 49938 + 406 = 50344
Step 125: 50344 + 406 = 50750
Step 126: 50750 + 406 = 51156
Step 127: 51156 + 406 = 51562
Step 128: 51562 + 406 = 51968
Step 129: 51968 + 406 = 52374
Step 130: 52374 + 406 = 52780
Step 131: 52780 + 406 = 53186
Step 132: 53186 + 406 = 53592
Step 133: 53592 + 406 = 53998
Step 134: 53998 + 406 = 54404
Step 135: 54404 + 406 = 54810
Step 136: 54810 + 406 = 55216
Step 137: 55216 + 406 = 55622
Step 138: 55622 + 406 = 56028
Step 139: 56028 + 406 = 56434
Step 140: 56434 + 406 = 56840
Step 141: 56840 + 406 = 57246
Step 142: 57246 + 406 = 57652
Step 143: 57652 + 406 = 58058
Step 144: 58058 + 406 = 58464
Step 145: 58464 + 406 = 58870
Step 146: 58870 + 406 = 59276
Step 147: 59276 + 406 = 59682
Step 148: 59682 + 406 = 60088
Step 149: 60088 + 406 = 60494
Step 150: 60494 + 406 = 60900
Step 151: 60900 + 406 = 61306
Step 152: 61306 + 406 = 61712
Step 153: 61712 + 406 = 62118
Step 154: 62118 + 406 = 62524
Step 155: 62524 + 406 = 62930
Step 156: 62930 + 406 = 63336
Step 157: 63336 + 406 = 63742
Step 158: 63742 + 406 = 64148
Step 159: 64148 + 406 = 64554
Step 160: 64554 + 406 = 64960
Step 161: 64960 + 406 = 65366
Step 162: 65366 + 406 = 65772
Step 163: 65772 + 406 = 66178
Step 164: 66178 + 406 = 66584
Step 165: 66584 + 406 = 66990
Step 166: 66990 + 406 = 67396
Step 167: 67396 + 406 = 67802
Step 168: 67802 + 406 = 68208
Step 169: 68208 + 406 = 68614
Step 170: 68614 + 406 = 69020
Step 171: 69020 + 406 = 69426
Step 172: 69426 + 406 = 69832
Step 173: 69832 + 406 = 70238
Step 174: 70238 + 406 = 70644
Step 175: 70644 + 406 = 71050
Step 176: 71050 + 406 = 71456
Step 177: 71456 + 406 = 71862
Step 178: 71862 + 406 = 72268
Step 179: 72268 + 406 = 72674
Step 180: 72674 + 406 = 73080
Step 181: 73080 + 406 = 73486
Step 182: 73486 + 406 = 73892
Step 183: 73892 + 406 = 74298
Step 184: 74298 + 406 = 74704
Step 185: 74704 + 406 = 75110
Step 186: 75110 + 406 = 75516
Step 187: 75516 + 406 = 75922
Step 188: 75922 + 406 = 76328
Step 189: 76328 + 406 = 76734
Step 190: 76734 + 406 = 77140
Step 191: 77140 + 406 = 77546
Step 192: 77546 + 406 = 77952
Step 193: 77952 + 406 = 78358
Step 194: 78358 + 406 = 78764
Step 195: 78764 + 406 = 79170
Step 196: 79170 + 406 = 79576
Step 197: 79576 + 406 = 79982
Step 198: 79982 + 406 = 80388
Step 199: 80388 + 406 = 80794
Step 200: 80794 + 406 = 81200
Step 201: 81200 + 406 = 81606
Step 202: 81606 + 406 = 82012
Step 203: 82012 + 406 = 82418
Step 204: 82418 + 406 = 82824
Step 205: 82824 + 406 = 83230
Step 206: 83230 + 406 = 83636
Step 207: 83636 + 406 = 84042
Step 208: 84042 + 406 = 84448
Step 209: 84448 + 406 = 84854
Step 210: 84854 + 406 = 85260
Step 211: 85260 + 406 = 85666
Step 212: 85666 + 406 = 86072
Step 213: 86072 + 406 = 86478
Step 214: 86478 + 406 = 86884
Step 215: 86884 + 406 = 87290
Step 216: 87290 + 406 = 87696
Step 217: 87696 + 406 = 88102
Step 218: 88102 + 406 = 88508
Step 219: 88508 + 406 = 88914
Step 220: 88914 + 406 = 89320
Step 221: 89320 + 406 = 89726
Step 222: 89726 + 406 = 90132
Step 223: 90132 + 406 = 90538
Step 224: 90538 + 406 = 90944
Step 225: 90944 + 406 = 91350
Step 226: 91350 + 406 = 91756
Step 227: 91756 + 406 = 92162
Step 228: 92162 + 406 = 92568
Step 229: 92568 + 406 = 92974
Step 230: 92974 + 406 = 93380
Step 231: 93380 + 406 = 93786
Step 232: 93786 + 406 = 94192
Step 233: 94192 + 406 = 94598
Step 234: 94598 + 406 = 95004
Step 235: 95004 + 406 = 95410
Step 236: 95410 + 406 = 95816
Step 237: 95816 + 406 = 96222
Step 238: 96222 + 406 = 96628
Step 239: 96628 + 406 = 97034
Step 240: 97034 + 406 = 97440
Step 241: 97440 + 406 = 97846
Step 242: 97846 + 406 = 98252
Step 243: 98252 + 406 = 98658
Step 244: 98658 + 406 = 99064
Step 245: 99064 + 406 = 99470
Step 246: 99470 + 406 = 99876
Step 247: 99876 + 406 = 100282
Step 248: 100282 + 406 = 100688
Step 249: 100688 + 406 = 101094
Step 250: 101094 + 406 = 101500
Step 251: 101500 + 406 = 101906
Step 252: 101906 + 406 = 102312
Step 253: 102312 + 406 = 102718
Step 254: 102718 + 406 = 103124
Step 255: 103124 + 406 = 103530
Step 256: 103530 + 406 = 103936
Step 257: 103936 + 406 = 104342
Step 258: 104342 + 406 = 104748
Step 259: 104748 + 406 = 105154
Step 260: 105154 + 406 = 105560
Step 261: 105560 + 406 = 105966
Step 262: 105966 + 406 = 106372
Step 263: 106372 + 406 = 106778
Step 264: 106778 + 406 = 107184
Step 265: 107184 + 406 = 107590
Step 266: 107590 + 406 = 107996
Step 267: 107996 + 406 = 108402
Step 268: 108402 + 406 = 108808
Step 269: 108808 + 406 = 109214
Step 270: 109214 + 406 = 109620
Step 271: 109620 + 406 = 110026
Step 272: 110026 + 406 = 110432
Step 273: 110432 + 406 = 110838
Step 274: 110838 + 406 = 111244
Step 275: 111244 + 406 = 111650
Step 276: 111650 + 406 = 112056
Step 277: 112056 + 406 = 112462
Step 278: 112462 + 406 = 112868
Step 279: 112868 + 406 = 113274
Step 280: 113274 + 406 = 113680
Step 281: 113680 + 406 = 114086
Step 282: 114086 + 406 = 114492
Step 283: 114492 + 406 = 114898
Step 284: 114898 + 406 = 115304
Step 285: 115304 + 406 = 115710
Step 286: 115710 + 406 = 116116
Step 287: 116116 + 406 = 116522
Step 288: 116522 + 406 = 116928
Step 289: 116928 + 406 = 117334
Step 290: 117334 + 406 = 117740
Step 291: 117740 + 406 = 118146
Step 292: 118146 + 406 = 118552
Step 293: 118552 + 406 = 118958
Step 294: 118958 + 406 = 119364
Step 295: 119364 + 406 = 119770
Step 296: 119770 + 406 = 120176
Step 297: 120176 + 406 = 120582
Step 298: 120582 + 406 = 120988
Step 299: 120988 + 406 = 121394
Step 300: 121394 + 406 = 121800
Step 301: 121800 + 406 = 122206
Step 302: 122206 + 406 = 122612
Step 303: 122612 + 406 = 123018
Step 304: 123018 + 406 = 123424
Step 305: 123424 + 406 = 123830
Step 306: 123830 + 406 = 124236
Step 307: 124236 + 406 = 124642
Step 308: 124642 + 406 = 125048
Step 309: 125048 + 406 = 125454
Step 310: 125454 + 406 = 125860
Step 311: 125860 + 406 = 126266
Step 312: 126266 + 406 = 126672
Step 313: 126672 + 406 = 127078
Step 314: 127078 + 406 = 127484
Step 315: 127484 + 406 = 127890
Step 316: 127890 + 406 = 128296
Step 317: 128296 + 406 = 128702
Step 318: 128702 + 406 = 129108
Step 319: 129108 + 406 = 129514
Step 320: 129514 + 406 = 129920
Step 321: 129920 + 406 = 130326
Step 322: 130326 + 406 = 130732
Step 323: 130732 + 406 = 131138
Step 324: 131138 + 406 = 131544
Step 325: 131544 + 406 = 131950
Step 326: 131950 + 406 = 132356
Step 327: 132356 + 406 = 132762
Step 328: 132762 + 406 = 133168
Step 329: 133168 + 406 = 133574
Step 330: 133574 + 406 = 133980
Step 331: 133980 + 406 = 134386
Step 332: 134386 + 406 = 134792
Step 333: 134792 + 406 = 135198
Step 334: 135198 + 406 = 135604
Step 335: 135604 + 406 = 136010
Step 336: 136010 + 406 = 136416
Step 337: 136416 + 406 = 136822
Step 338: 136822 + 406 = 137228
Step 339: 137228 + 406 = 137634
Step 340: 137634 + 406 = 138040
Step 341: 138040 + 406 = 138446
Step 342: 138446 + 406 = 138852
Step 343: 138852 + 406 = 139258
Step 344: 139258 + 406 = 139664
Step 345: 139664 + 406 = 140070
Step 346: 140070 + 406 = 140476
Step 347: 140476 + 406 = 140882
Step 348: 140882 + 406 = 141288
Step 349: 141288 + 406 = 141694
Step 350: 141694 + 406 = 142100
Step 351: 142100 + 406 = 142506
Step 352: 142506 + 406 = 142912
Step 353: 142912 + 406 = 143318
Step 354: 143318 + 406 = 143724
Step 355: 143724 + 406 = 144130
Step 356: 144130 + 406 = 144536
Step 357: 144536 + 406 = 144942
Step 358: 144942 + 406 = 145348
Step 359: 145348 + 406 = 145754
Step 360: 145754 + 406 = 146160
Step 361: 146160 + 406 = 146566
Step 362: 146566 + 406 = 146972
Step 363: 146972 + 406 = 147378
Step 364: 147378 + 406 = 147784
Step 365: 147784 + 406 = 148190
Step 366: 148190 + 406 = 148596
Step 367: 148596 + 406 = 149002
Step 368: 149002 + 406 = 149408
Step 369: 149408 + 406 = 149814
Step 370: 149814 + 406 = 150220
Step 371: 150220 + 406 = 150626
Step 372: 150626 + 406 = 151032
Step 373: 151032 + 406 = 151438
Step 374: 151438 + 406 = 151844
Step 375: 151844 + 406 = 152250
Step 376: 152250 + 406 = 152656
Step 377: 152656 + 406 = 153062
Step 378: 153062 + 406 = 153468
Step 379: 153468 + 406 = 153874
Step 380: 153874 + 406 = 154280
Step 381: 154280 + 406 = 154686
Step 382: 154686 + 406 = 155092
Step 383: 155092 + 406 = 155498
Step 384: 155498 + 406 = 155904
Step 385: 155904 + 406 = 156310
Step 386: 156310 + 406 = 156716
Step 387: 156716 + 406 = 157122
Step 388: 157122 + 406 = 157528
Step 389: 157528 + 406 = 157934
Step 390: 157934 + 406 = 158340
Step 391: 158340 + 406 = 158746
Step 392: 158746 + 406 = 159152
Step 393: 159152 + 406 = 159558
Step 394: 159558 + 406 = 159964
Step 395: 159964 + 406 = 160370
Step 396: 160370 + 406 = 160776
Step 397: 160776 + 406 = 161182
Step 398: 161182 + 406 = 161588
Step 399: 161588 + 406 = 161994
Step 400: 161994 + 406 = 162400
Step 401: 162400 + 406 = 162806
Step 402: 162806 + 406 = 163212
Step 403: 163212 + 406 = 163618
Step 404: 163618 + 406 = 164024
Step 405: 164024 + 406 = 164430
Step 406: 164430 + 406 = 164836
Step 407: 164836 + 406 = 165242
Step 408: 165242 + 406 = 165648
Step 409: 165648 + 406 = 166054
Step 410: 166054 + 406 = 166460
Step 411: 166460 + 406 = 166866
Step 412: 166866 + 406 = 167272
Step 413: 167272 + 406 = 167678
Step 414: 167678 + 406 = 168084
Step 415: 168084 + 406 = 168490
Step 416: 168490 + 406 = 168896
Step 417: 168896 + 406 = 169302
Step 418: 169302 + 406 = 169708
Step 419: 169708 + 406 = 170114
Step 420: 170114 + 406 = 170520
Step 421: 170520 + 406 = 170926
Step 422: 170926 + 406 = 171332
Step 423: 171332 + 406 = 171738

So, 406*423 = 171738