Alright, let's solve this math problem step by step. First, we have the number 921. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 405. So, we're going to take the number 921 and add it to itself 405 times.
Step 1: 0 + 921 = 921
Step 2: 921 + 921 = 1842
Step 3: 1842 + 921 = 2763
Step 4: 2763 + 921 = 3684
Step 5: 3684 + 921 = 4605
Step 6: 4605 + 921 = 5526
Step 7: 5526 + 921 = 6447
Step 8: 6447 + 921 = 7368
Step 9: 7368 + 921 = 8289
Step 10: 8289 + 921 = 9210
Step 11: 9210 + 921 = 10131
Step 12: 10131 + 921 = 11052
Step 13: 11052 + 921 = 11973
Step 14: 11973 + 921 = 12894
Step 15: 12894 + 921 = 13815
Step 16: 13815 + 921 = 14736
Step 17: 14736 + 921 = 15657
Step 18: 15657 + 921 = 16578
Step 19: 16578 + 921 = 17499
Step 20: 17499 + 921 = 18420
Step 21: 18420 + 921 = 19341
Step 22: 19341 + 921 = 20262
Step 23: 20262 + 921 = 21183
Step 24: 21183 + 921 = 22104
Step 25: 22104 + 921 = 23025
Step 26: 23025 + 921 = 23946
Step 27: 23946 + 921 = 24867
Step 28: 24867 + 921 = 25788
Step 29: 25788 + 921 = 26709
Step 30: 26709 + 921 = 27630
Step 31: 27630 + 921 = 28551
Step 32: 28551 + 921 = 29472
Step 33: 29472 + 921 = 30393
Step 34: 30393 + 921 = 31314
Step 35: 31314 + 921 = 32235
Step 36: 32235 + 921 = 33156
Step 37: 33156 + 921 = 34077
Step 38: 34077 + 921 = 34998
Step 39: 34998 + 921 = 35919
Step 40: 35919 + 921 = 36840
Step 41: 36840 + 921 = 37761
Step 42: 37761 + 921 = 38682
Step 43: 38682 + 921 = 39603
Step 44: 39603 + 921 = 40524
Step 45: 40524 + 921 = 41445
Step 46: 41445 + 921 = 42366
Step 47: 42366 + 921 = 43287
Step 48: 43287 + 921 = 44208
Step 49: 44208 + 921 = 45129
Step 50: 45129 + 921 = 46050
Step 51: 46050 + 921 = 46971
Step 52: 46971 + 921 = 47892
Step 53: 47892 + 921 = 48813
Step 54: 48813 + 921 = 49734
Step 55: 49734 + 921 = 50655
Step 56: 50655 + 921 = 51576
Step 57: 51576 + 921 = 52497
Step 58: 52497 + 921 = 53418
Step 59: 53418 + 921 = 54339
Step 60: 54339 + 921 = 55260
Step 61: 55260 + 921 = 56181
Step 62: 56181 + 921 = 57102
Step 63: 57102 + 921 = 58023
Step 64: 58023 + 921 = 58944
Step 65: 58944 + 921 = 59865
Step 66: 59865 + 921 = 60786
Step 67: 60786 + 921 = 61707
Step 68: 61707 + 921 = 62628
Step 69: 62628 + 921 = 63549
Step 70: 63549 + 921 = 64470
Step 71: 64470 + 921 = 65391
Step 72: 65391 + 921 = 66312
Step 73: 66312 + 921 = 67233
Step 74: 67233 + 921 = 68154
Step 75: 68154 + 921 = 69075
Step 76: 69075 + 921 = 69996
Step 77: 69996 + 921 = 70917
Step 78: 70917 + 921 = 71838
Step 79: 71838 + 921 = 72759
Step 80: 72759 + 921 = 73680
Step 81: 73680 + 921 = 74601
Step 82: 74601 + 921 = 75522
Step 83: 75522 + 921 = 76443
Step 84: 76443 + 921 = 77364
Step 85: 77364 + 921 = 78285
Step 86: 78285 + 921 = 79206
Step 87: 79206 + 921 = 80127
Step 88: 80127 + 921 = 81048
Step 89: 81048 + 921 = 81969
Step 90: 81969 + 921 = 82890
Step 91: 82890 + 921 = 83811
Step 92: 83811 + 921 = 84732
Step 93: 84732 + 921 = 85653
Step 94: 85653 + 921 = 86574
Step 95: 86574 + 921 = 87495
Step 96: 87495 + 921 = 88416
Step 97: 88416 + 921 = 89337
Step 98: 89337 + 921 = 90258
Step 99: 90258 + 921 = 91179
Step 100: 91179 + 921 = 92100
Step 101: 92100 + 921 = 93021
Step 102: 93021 + 921 = 93942
Step 103: 93942 + 921 = 94863
Step 104: 94863 + 921 = 95784
Step 105: 95784 + 921 = 96705
Step 106: 96705 + 921 = 97626
Step 107: 97626 + 921 = 98547
Step 108: 98547 + 921 = 99468
Step 109: 99468 + 921 = 100389
Step 110: 100389 + 921 = 101310
Step 111: 101310 + 921 = 102231
Step 112: 102231 + 921 = 103152
Step 113: 103152 + 921 = 104073
Step 114: 104073 + 921 = 104994
Step 115: 104994 + 921 = 105915
Step 116: 105915 + 921 = 106836
Step 117: 106836 + 921 = 107757
Step 118: 107757 + 921 = 108678
Step 119: 108678 + 921 = 109599
Step 120: 109599 + 921 = 110520
Step 121: 110520 + 921 = 111441
Step 122: 111441 + 921 = 112362
Step 123: 112362 + 921 = 113283
Step 124: 113283 + 921 = 114204
Step 125: 114204 + 921 = 115125
Step 126: 115125 + 921 = 116046
Step 127: 116046 + 921 = 116967
Step 128: 116967 + 921 = 117888
Step 129: 117888 + 921 = 118809
Step 130: 118809 + 921 = 119730
Step 131: 119730 + 921 = 120651
Step 132: 120651 + 921 = 121572
Step 133: 121572 + 921 = 122493
Step 134: 122493 + 921 = 123414
Step 135: 123414 + 921 = 124335
Step 136: 124335 + 921 = 125256
Step 137: 125256 + 921 = 126177
Step 138: 126177 + 921 = 127098
Step 139: 127098 + 921 = 128019
Step 140: 128019 + 921 = 128940
Step 141: 128940 + 921 = 129861
Step 142: 129861 + 921 = 130782
Step 143: 130782 + 921 = 131703
Step 144: 131703 + 921 = 132624
Step 145: 132624 + 921 = 133545
Step 146: 133545 + 921 = 134466
Step 147: 134466 + 921 = 135387
Step 148: 135387 + 921 = 136308
Step 149: 136308 + 921 = 137229
Step 150: 137229 + 921 = 138150
Step 151: 138150 + 921 = 139071
Step 152: 139071 + 921 = 139992
Step 153: 139992 + 921 = 140913
Step 154: 140913 + 921 = 141834
Step 155: 141834 + 921 = 142755
Step 156: 142755 + 921 = 143676
Step 157: 143676 + 921 = 144597
Step 158: 144597 + 921 = 145518
Step 159: 145518 + 921 = 146439
Step 160: 146439 + 921 = 147360
Step 161: 147360 + 921 = 148281
Step 162: 148281 + 921 = 149202
Step 163: 149202 + 921 = 150123
Step 164: 150123 + 921 = 151044
Step 165: 151044 + 921 = 151965
Step 166: 151965 + 921 = 152886
Step 167: 152886 + 921 = 153807
Step 168: 153807 + 921 = 154728
Step 169: 154728 + 921 = 155649
Step 170: 155649 + 921 = 156570
Step 171: 156570 + 921 = 157491
Step 172: 157491 + 921 = 158412
Step 173: 158412 + 921 = 159333
Step 174: 159333 + 921 = 160254
Step 175: 160254 + 921 = 161175
Step 176: 161175 + 921 = 162096
Step 177: 162096 + 921 = 163017
Step 178: 163017 + 921 = 163938
Step 179: 163938 + 921 = 164859
Step 180: 164859 + 921 = 165780
Step 181: 165780 + 921 = 166701
Step 182: 166701 + 921 = 167622
Step 183: 167622 + 921 = 168543
Step 184: 168543 + 921 = 169464
Step 185: 169464 + 921 = 170385
Step 186: 170385 + 921 = 171306
Step 187: 171306 + 921 = 172227
Step 188: 172227 + 921 = 173148
Step 189: 173148 + 921 = 174069
Step 190: 174069 + 921 = 174990
Step 191: 174990 + 921 = 175911
Step 192: 175911 + 921 = 176832
Step 193: 176832 + 921 = 177753
Step 194: 177753 + 921 = 178674
Step 195: 178674 + 921 = 179595
Step 196: 179595 + 921 = 180516
Step 197: 180516 + 921 = 181437
Step 198: 181437 + 921 = 182358
Step 199: 182358 + 921 = 183279
Step 200: 183279 + 921 = 184200
Step 201: 184200 + 921 = 185121
Step 202: 185121 + 921 = 186042
Step 203: 186042 + 921 = 186963
Step 204: 186963 + 921 = 187884
Step 205: 187884 + 921 = 188805
Step 206: 188805 + 921 = 189726
Step 207: 189726 + 921 = 190647
Step 208: 190647 + 921 = 191568
Step 209: 191568 + 921 = 192489
Step 210: 192489 + 921 = 193410
Step 211: 193410 + 921 = 194331
Step 212: 194331 + 921 = 195252
Step 213: 195252 + 921 = 196173
Step 214: 196173 + 921 = 197094
Step 215: 197094 + 921 = 198015
Step 216: 198015 + 921 = 198936
Step 217: 198936 + 921 = 199857
Step 218: 199857 + 921 = 200778
Step 219: 200778 + 921 = 201699
Step 220: 201699 + 921 = 202620
Step 221: 202620 + 921 = 203541
Step 222: 203541 + 921 = 204462
Step 223: 204462 + 921 = 205383
Step 224: 205383 + 921 = 206304
Step 225: 206304 + 921 = 207225
Step 226: 207225 + 921 = 208146
Step 227: 208146 + 921 = 209067
Step 228: 209067 + 921 = 209988
Step 229: 209988 + 921 = 210909
Step 230: 210909 + 921 = 211830
Step 231: 211830 + 921 = 212751
Step 232: 212751 + 921 = 213672
Step 233: 213672 + 921 = 214593
Step 234: 214593 + 921 = 215514
Step 235: 215514 + 921 = 216435
Step 236: 216435 + 921 = 217356
Step 237: 217356 + 921 = 218277
Step 238: 218277 + 921 = 219198
Step 239: 219198 + 921 = 220119
Step 240: 220119 + 921 = 221040
Step 241: 221040 + 921 = 221961
Step 242: 221961 + 921 = 222882
Step 243: 222882 + 921 = 223803
Step 244: 223803 + 921 = 224724
Step 245: 224724 + 921 = 225645
Step 246: 225645 + 921 = 226566
Step 247: 226566 + 921 = 227487
Step 248: 227487 + 921 = 228408
Step 249: 228408 + 921 = 229329
Step 250: 229329 + 921 = 230250
Step 251: 230250 + 921 = 231171
Step 252: 231171 + 921 = 232092
Step 253: 232092 + 921 = 233013
Step 254: 233013 + 921 = 233934
Step 255: 233934 + 921 = 234855
Step 256: 234855 + 921 = 235776
Step 257: 235776 + 921 = 236697
Step 258: 236697 + 921 = 237618
Step 259: 237618 + 921 = 238539
Step 260: 238539 + 921 = 239460
Step 261: 239460 + 921 = 240381
Step 262: 240381 + 921 = 241302
Step 263: 241302 + 921 = 242223
Step 264: 242223 + 921 = 243144
Step 265: 243144 + 921 = 244065
Step 266: 244065 + 921 = 244986
Step 267: 244986 + 921 = 245907
Step 268: 245907 + 921 = 246828
Step 269: 246828 + 921 = 247749
Step 270: 247749 + 921 = 248670
Step 271: 248670 + 921 = 249591
Step 272: 249591 + 921 = 250512
Step 273: 250512 + 921 = 251433
Step 274: 251433 + 921 = 252354
Step 275: 252354 + 921 = 253275
Step 276: 253275 + 921 = 254196
Step 277: 254196 + 921 = 255117
Step 278: 255117 + 921 = 256038
Step 279: 256038 + 921 = 256959
Step 280: 256959 + 921 = 257880
Step 281: 257880 + 921 = 258801
Step 282: 258801 + 921 = 259722
Step 283: 259722 + 921 = 260643
Step 284: 260643 + 921 = 261564
Step 285: 261564 + 921 = 262485
Step 286: 262485 + 921 = 263406
Step 287: 263406 + 921 = 264327
Step 288: 264327 + 921 = 265248
Step 289: 265248 + 921 = 266169
Step 290: 266169 + 921 = 267090
Step 291: 267090 + 921 = 268011
Step 292: 268011 + 921 = 268932
Step 293: 268932 + 921 = 269853
Step 294: 269853 + 921 = 270774
Step 295: 270774 + 921 = 271695
Step 296: 271695 + 921 = 272616
Step 297: 272616 + 921 = 273537
Step 298: 273537 + 921 = 274458
Step 299: 274458 + 921 = 275379
Step 300: 275379 + 921 = 276300
Step 301: 276300 + 921 = 277221
Step 302: 277221 + 921 = 278142
Step 303: 278142 + 921 = 279063
Step 304: 279063 + 921 = 279984
Step 305: 279984 + 921 = 280905
Step 306: 280905 + 921 = 281826
Step 307: 281826 + 921 = 282747
Step 308: 282747 + 921 = 283668
Step 309: 283668 + 921 = 284589
Step 310: 284589 + 921 = 285510
Step 311: 285510 + 921 = 286431
Step 312: 286431 + 921 = 287352
Step 313: 287352 + 921 = 288273
Step 314: 288273 + 921 = 289194
Step 315: 289194 + 921 = 290115
Step 316: 290115 + 921 = 291036
Step 317: 291036 + 921 = 291957
Step 318: 291957 + 921 = 292878
Step 319: 292878 + 921 = 293799
Step 320: 293799 + 921 = 294720
Step 321: 294720 + 921 = 295641
Step 322: 295641 + 921 = 296562
Step 323: 296562 + 921 = 297483
Step 324: 297483 + 921 = 298404
Step 325: 298404 + 921 = 299325
Step 326: 299325 + 921 = 300246
Step 327: 300246 + 921 = 301167
Step 328: 301167 + 921 = 302088
Step 329: 302088 + 921 = 303009
Step 330: 303009 + 921 = 303930
Step 331: 303930 + 921 = 304851
Step 332: 304851 + 921 = 305772
Step 333: 305772 + 921 = 306693
Step 334: 306693 + 921 = 307614
Step 335: 307614 + 921 = 308535
Step 336: 308535 + 921 = 309456
Step 337: 309456 + 921 = 310377
Step 338: 310377 + 921 = 311298
Step 339: 311298 + 921 = 312219
Step 340: 312219 + 921 = 313140
Step 341: 313140 + 921 = 314061
Step 342: 314061 + 921 = 314982
Step 343: 314982 + 921 = 315903
Step 344: 315903 + 921 = 316824
Step 345: 316824 + 921 = 317745
Step 346: 317745 + 921 = 318666
Step 347: 318666 + 921 = 319587
Step 348: 319587 + 921 = 320508
Step 349: 320508 + 921 = 321429
Step 350: 321429 + 921 = 322350
Step 351: 322350 + 921 = 323271
Step 352: 323271 + 921 = 324192
Step 353: 324192 + 921 = 325113
Step 354: 325113 + 921 = 326034
Step 355: 326034 + 921 = 326955
Step 356: 326955 + 921 = 327876
Step 357: 327876 + 921 = 328797
Step 358: 328797 + 921 = 329718
Step 359: 329718 + 921 = 330639
Step 360: 330639 + 921 = 331560
Step 361: 331560 + 921 = 332481
Step 362: 332481 + 921 = 333402
Step 363: 333402 + 921 = 334323
Step 364: 334323 + 921 = 335244
Step 365: 335244 + 921 = 336165
Step 366: 336165 + 921 = 337086
Step 367: 337086 + 921 = 338007
Step 368: 338007 + 921 = 338928
Step 369: 338928 + 921 = 339849
Step 370: 339849 + 921 = 340770
Step 371: 340770 + 921 = 341691
Step 372: 341691 + 921 = 342612
Step 373: 342612 + 921 = 343533
Step 374: 343533 + 921 = 344454
Step 375: 344454 + 921 = 345375
Step 376: 345375 + 921 = 346296
Step 377: 346296 + 921 = 347217
Step 378: 347217 + 921 = 348138
Step 379: 348138 + 921 = 349059
Step 380: 349059 + 921 = 349980
Step 381: 349980 + 921 = 350901
Step 382: 350901 + 921 = 351822
Step 383: 351822 + 921 = 352743
Step 384: 352743 + 921 = 353664
Step 385: 353664 + 921 = 354585
Step 386: 354585 + 921 = 355506
Step 387: 355506 + 921 = 356427
Step 388: 356427 + 921 = 357348
Step 389: 357348 + 921 = 358269
Step 390: 358269 + 921 = 359190
Step 391: 359190 + 921 = 360111
Step 392: 360111 + 921 = 361032
Step 393: 361032 + 921 = 361953
Step 394: 361953 + 921 = 362874
Step 395: 362874 + 921 = 363795
Step 396: 363795 + 921 = 364716
Step 397: 364716 + 921 = 365637
Step 398: 365637 + 921 = 366558
Step 399: 366558 + 921 = 367479
Step 400: 367479 + 921 = 368400
Step 401: 368400 + 921 = 369321
Step 402: 369321 + 921 = 370242
Step 403: 370242 + 921 = 371163
Step 404: 371163 + 921 = 372084
Step 405: 372084 + 921 = 373005

So, 921*405 = 373005