Sure thing, let's get straight to it. We start with 801 and we're going to multiply it by 420, which means adding 801 to itself 420 times.
Step 1: 0 + 801 = 801
Step 2: 801 + 801 = 1602
Step 3: 1602 + 801 = 2403
Step 4: 2403 + 801 = 3204
Step 5: 3204 + 801 = 4005
Step 6: 4005 + 801 = 4806
Step 7: 4806 + 801 = 5607
Step 8: 5607 + 801 = 6408
Step 9: 6408 + 801 = 7209
Step 10: 7209 + 801 = 8010
Step 11: 8010 + 801 = 8811
Step 12: 8811 + 801 = 9612
Step 13: 9612 + 801 = 10413
Step 14: 10413 + 801 = 11214
Step 15: 11214 + 801 = 12015
Step 16: 12015 + 801 = 12816
Step 17: 12816 + 801 = 13617
Step 18: 13617 + 801 = 14418
Step 19: 14418 + 801 = 15219
Step 20: 15219 + 801 = 16020
Step 21: 16020 + 801 = 16821
Step 22: 16821 + 801 = 17622
Step 23: 17622 + 801 = 18423
Step 24: 18423 + 801 = 19224
Step 25: 19224 + 801 = 20025
Step 26: 20025 + 801 = 20826
Step 27: 20826 + 801 = 21627
Step 28: 21627 + 801 = 22428
Step 29: 22428 + 801 = 23229
Step 30: 23229 + 801 = 24030
Step 31: 24030 + 801 = 24831
Step 32: 24831 + 801 = 25632
Step 33: 25632 + 801 = 26433
Step 34: 26433 + 801 = 27234
Step 35: 27234 + 801 = 28035
Step 36: 28035 + 801 = 28836
Step 37: 28836 + 801 = 29637
Step 38: 29637 + 801 = 30438
Step 39: 30438 + 801 = 31239
Step 40: 31239 + 801 = 32040
Step 41: 32040 + 801 = 32841
Step 42: 32841 + 801 = 33642
Step 43: 33642 + 801 = 34443
Step 44: 34443 + 801 = 35244
Step 45: 35244 + 801 = 36045
Step 46: 36045 + 801 = 36846
Step 47: 36846 + 801 = 37647
Step 48: 37647 + 801 = 38448
Step 49: 38448 + 801 = 39249
Step 50: 39249 + 801 = 40050
Step 51: 40050 + 801 = 40851
Step 52: 40851 + 801 = 41652
Step 53: 41652 + 801 = 42453
Step 54: 42453 + 801 = 43254
Step 55: 43254 + 801 = 44055
Step 56: 44055 + 801 = 44856
Step 57: 44856 + 801 = 45657
Step 58: 45657 + 801 = 46458
Step 59: 46458 + 801 = 47259
Step 60: 47259 + 801 = 48060
Step 61: 48060 + 801 = 48861
Step 62: 48861 + 801 = 49662
Step 63: 49662 + 801 = 50463
Step 64: 50463 + 801 = 51264
Step 65: 51264 + 801 = 52065
Step 66: 52065 + 801 = 52866
Step 67: 52866 + 801 = 53667
Step 68: 53667 + 801 = 54468
Step 69: 54468 + 801 = 55269
Step 70: 55269 + 801 = 56070
Step 71: 56070 + 801 = 56871
Step 72: 56871 + 801 = 57672
Step 73: 57672 + 801 = 58473
Step 74: 58473 + 801 = 59274
Step 75: 59274 + 801 = 60075
Step 76: 60075 + 801 = 60876
Step 77: 60876 + 801 = 61677
Step 78: 61677 + 801 = 62478
Step 79: 62478 + 801 = 63279
Step 80: 63279 + 801 = 64080
Step 81: 64080 + 801 = 64881
Step 82: 64881 + 801 = 65682
Step 83: 65682 + 801 = 66483
Step 84: 66483 + 801 = 67284
Step 85: 67284 + 801 = 68085
Step 86: 68085 + 801 = 68886
Step 87: 68886 + 801 = 69687
Step 88: 69687 + 801 = 70488
Step 89: 70488 + 801 = 71289
Step 90: 71289 + 801 = 72090
Step 91: 72090 + 801 = 72891
Step 92: 72891 + 801 = 73692
Step 93: 73692 + 801 = 74493
Step 94: 74493 + 801 = 75294
Step 95: 75294 + 801 = 76095
Step 96: 76095 + 801 = 76896
Step 97: 76896 + 801 = 77697
Step 98: 77697 + 801 = 78498
Step 99: 78498 + 801 = 79299
Step 100: 79299 + 801 = 80100
Step 101: 80100 + 801 = 80901
Step 102: 80901 + 801 = 81702
Step 103: 81702 + 801 = 82503
Step 104: 82503 + 801 = 83304
Step 105: 83304 + 801 = 84105
Step 106: 84105 + 801 = 84906
Step 107: 84906 + 801 = 85707
Step 108: 85707 + 801 = 86508
Step 109: 86508 + 801 = 87309
Step 110: 87309 + 801 = 88110
Step 111: 88110 + 801 = 88911
Step 112: 88911 + 801 = 89712
Step 113: 89712 + 801 = 90513
Step 114: 90513 + 801 = 91314
Step 115: 91314 + 801 = 92115
Step 116: 92115 + 801 = 92916
Step 117: 92916 + 801 = 93717
Step 118: 93717 + 801 = 94518
Step 119: 94518 + 801 = 95319
Step 120: 95319 + 801 = 96120
Step 121: 96120 + 801 = 96921
Step 122: 96921 + 801 = 97722
Step 123: 97722 + 801 = 98523
Step 124: 98523 + 801 = 99324
Step 125: 99324 + 801 = 100125
Step 126: 100125 + 801 = 100926
Step 127: 100926 + 801 = 101727
Step 128: 101727 + 801 = 102528
Step 129: 102528 + 801 = 103329
Step 130: 103329 + 801 = 104130
Step 131: 104130 + 801 = 104931
Step 132: 104931 + 801 = 105732
Step 133: 105732 + 801 = 106533
Step 134: 106533 + 801 = 107334
Step 135: 107334 + 801 = 108135
Step 136: 108135 + 801 = 108936
Step 137: 108936 + 801 = 109737
Step 138: 109737 + 801 = 110538
Step 139: 110538 + 801 = 111339
Step 140: 111339 + 801 = 112140
Step 141: 112140 + 801 = 112941
Step 142: 112941 + 801 = 113742
Step 143: 113742 + 801 = 114543
Step 144: 114543 + 801 = 115344
Step 145: 115344 + 801 = 116145
Step 146: 116145 + 801 = 116946
Step 147: 116946 + 801 = 117747
Step 148: 117747 + 801 = 118548
Step 149: 118548 + 801 = 119349
Step 150: 119349 + 801 = 120150
Step 151: 120150 + 801 = 120951
Step 152: 120951 + 801 = 121752
Step 153: 121752 + 801 = 122553
Step 154: 122553 + 801 = 123354
Step 155: 123354 + 801 = 124155
Step 156: 124155 + 801 = 124956
Step 157: 124956 + 801 = 125757
Step 158: 125757 + 801 = 126558
Step 159: 126558 + 801 = 127359
Step 160: 127359 + 801 = 128160
Step 161: 128160 + 801 = 128961
Step 162: 128961 + 801 = 129762
Step 163: 129762 + 801 = 130563
Step 164: 130563 + 801 = 131364
Step 165: 131364 + 801 = 132165
Step 166: 132165 + 801 = 132966
Step 167: 132966 + 801 = 133767
Step 168: 133767 + 801 = 134568
Step 169: 134568 + 801 = 135369
Step 170: 135369 + 801 = 136170
Step 171: 136170 + 801 = 136971
Step 172: 136971 + 801 = 137772
Step 173: 137772 + 801 = 138573
Step 174: 138573 + 801 = 139374
Step 175: 139374 + 801 = 140175
Step 176: 140175 + 801 = 140976
Step 177: 140976 + 801 = 141777
Step 178: 141777 + 801 = 142578
Step 179: 142578 + 801 = 143379
Step 180: 143379 + 801 = 144180
Step 181: 144180 + 801 = 144981
Step 182: 144981 + 801 = 145782
Step 183: 145782 + 801 = 146583
Step 184: 146583 + 801 = 147384
Step 185: 147384 + 801 = 148185
Step 186: 148185 + 801 = 148986
Step 187: 148986 + 801 = 149787
Step 188: 149787 + 801 = 150588
Step 189: 150588 + 801 = 151389
Step 190: 151389 + 801 = 152190
Step 191: 152190 + 801 = 152991
Step 192: 152991 + 801 = 153792
Step 193: 153792 + 801 = 154593
Step 194: 154593 + 801 = 155394
Step 195: 155394 + 801 = 156195
Step 196: 156195 + 801 = 156996
Step 197: 156996 + 801 = 157797
Step 198: 157797 + 801 = 158598
Step 199: 158598 + 801 = 159399
Step 200: 159399 + 801 = 160200
Step 201: 160200 + 801 = 161001
Step 202: 161001 + 801 = 161802
Step 203: 161802 + 801 = 162603
Step 204: 162603 + 801 = 163404
Step 205: 163404 + 801 = 164205
Step 206: 164205 + 801 = 165006
Step 207: 165006 + 801 = 165807
Step 208: 165807 + 801 = 166608
Step 209: 166608 + 801 = 167409
Step 210: 167409 + 801 = 168210
Step 211: 168210 + 801 = 169011
Step 212: 169011 + 801 = 169812
Step 213: 169812 + 801 = 170613
Step 214: 170613 + 801 = 171414
Step 215: 171414 + 801 = 172215
Step 216: 172215 + 801 = 173016
Step 217: 173016 + 801 = 173817
Step 218: 173817 + 801 = 174618
Step 219: 174618 + 801 = 175419
Step 220: 175419 + 801 = 176220
Step 221: 176220 + 801 = 177021
Step 222: 177021 + 801 = 177822
Step 223: 177822 + 801 = 178623
Step 224: 178623 + 801 = 179424
Step 225: 179424 + 801 = 180225
Step 226: 180225 + 801 = 181026
Step 227: 181026 + 801 = 181827
Step 228: 181827 + 801 = 182628
Step 229: 182628 + 801 = 183429
Step 230: 183429 + 801 = 184230
Step 231: 184230 + 801 = 185031
Step 232: 185031 + 801 = 185832
Step 233: 185832 + 801 = 186633
Step 234: 186633 + 801 = 187434
Step 235: 187434 + 801 = 188235
Step 236: 188235 + 801 = 189036
Step 237: 189036 + 801 = 189837
Step 238: 189837 + 801 = 190638
Step 239: 190638 + 801 = 191439
Step 240: 191439 + 801 = 192240
Step 241: 192240 + 801 = 193041
Step 242: 193041 + 801 = 193842
Step 243: 193842 + 801 = 194643
Step 244: 194643 + 801 = 195444
Step 245: 195444 + 801 = 196245
Step 246: 196245 + 801 = 197046
Step 247: 197046 + 801 = 197847
Step 248: 197847 + 801 = 198648
Step 249: 198648 + 801 = 199449
Step 250: 199449 + 801 = 200250
Step 251: 200250 + 801 = 201051
Step 252: 201051 + 801 = 201852
Step 253: 201852 + 801 = 202653
Step 254: 202653 + 801 = 203454
Step 255: 203454 + 801 = 204255
Step 256: 204255 + 801 = 205056
Step 257: 205056 + 801 = 205857
Step 258: 205857 + 801 = 206658
Step 259: 206658 + 801 = 207459
Step 260: 207459 + 801 = 208260
Step 261: 208260 + 801 = 209061
Step 262: 209061 + 801 = 209862
Step 263: 209862 + 801 = 210663
Step 264: 210663 + 801 = 211464
Step 265: 211464 + 801 = 212265
Step 266: 212265 + 801 = 213066
Step 267: 213066 + 801 = 213867
Step 268: 213867 + 801 = 214668
Step 269: 214668 + 801 = 215469
Step 270: 215469 + 801 = 216270
Step 271: 216270 + 801 = 217071
Step 272: 217071 + 801 = 217872
Step 273: 217872 + 801 = 218673
Step 274: 218673 + 801 = 219474
Step 275: 219474 + 801 = 220275
Step 276: 220275 + 801 = 221076
Step 277: 221076 + 801 = 221877
Step 278: 221877 + 801 = 222678
Step 279: 222678 + 801 = 223479
Step 280: 223479 + 801 = 224280
Step 281: 224280 + 801 = 225081
Step 282: 225081 + 801 = 225882
Step 283: 225882 + 801 = 226683
Step 284: 226683 + 801 = 227484
Step 285: 227484 + 801 = 228285
Step 286: 228285 + 801 = 229086
Step 287: 229086 + 801 = 229887
Step 288: 229887 + 801 = 230688
Step 289: 230688 + 801 = 231489
Step 290: 231489 + 801 = 232290
Step 291: 232290 + 801 = 233091
Step 292: 233091 + 801 = 233892
Step 293: 233892 + 801 = 234693
Step 294: 234693 + 801 = 235494
Step 295: 235494 + 801 = 236295
Step 296: 236295 + 801 = 237096
Step 297: 237096 + 801 = 237897
Step 298: 237897 + 801 = 238698
Step 299: 238698 + 801 = 239499
Step 300: 239499 + 801 = 240300
Step 301: 240300 + 801 = 241101
Step 302: 241101 + 801 = 241902
Step 303: 241902 + 801 = 242703
Step 304: 242703 + 801 = 243504
Step 305: 243504 + 801 = 244305
Step 306: 244305 + 801 = 245106
Step 307: 245106 + 801 = 245907
Step 308: 245907 + 801 = 246708
Step 309: 246708 + 801 = 247509
Step 310: 247509 + 801 = 248310
Step 311: 248310 + 801 = 249111
Step 312: 249111 + 801 = 249912
Step 313: 249912 + 801 = 250713
Step 314: 250713 + 801 = 251514
Step 315: 251514 + 801 = 252315
Step 316: 252315 + 801 = 253116
Step 317: 253116 + 801 = 253917
Step 318: 253917 + 801 = 254718
Step 319: 254718 + 801 = 255519
Step 320: 255519 + 801 = 256320
Step 321: 256320 + 801 = 257121
Step 322: 257121 + 801 = 257922
Step 323: 257922 + 801 = 258723
Step 324: 258723 + 801 = 259524
Step 325: 259524 + 801 = 260325
Step 326: 260325 + 801 = 261126
Step 327: 261126 + 801 = 261927
Step 328: 261927 + 801 = 262728
Step 329: 262728 + 801 = 263529
Step 330: 263529 + 801 = 264330
Step 331: 264330 + 801 = 265131
Step 332: 265131 + 801 = 265932
Step 333: 265932 + 801 = 266733
Step 334: 266733 + 801 = 267534
Step 335: 267534 + 801 = 268335
Step 336: 268335 + 801 = 269136
Step 337: 269136 + 801 = 269937
Step 338: 269937 + 801 = 270738
Step 339: 270738 + 801 = 271539
Step 340: 271539 + 801 = 272340
Step 341: 272340 + 801 = 273141
Step 342: 273141 + 801 = 273942
Step 343: 273942 + 801 = 274743
Step 344: 274743 + 801 = 275544
Step 345: 275544 + 801 = 276345
Step 346: 276345 + 801 = 277146
Step 347: 277146 + 801 = 277947
Step 348: 277947 + 801 = 278748
Step 349: 278748 + 801 = 279549
Step 350: 279549 + 801 = 280350
Step 351: 280350 + 801 = 281151
Step 352: 281151 + 801 = 281952
Step 353: 281952 + 801 = 282753
Step 354: 282753 + 801 = 283554
Step 355: 283554 + 801 = 284355
Step 356: 284355 + 801 = 285156
Step 357: 285156 + 801 = 285957
Step 358: 285957 + 801 = 286758
Step 359: 286758 + 801 = 287559
Step 360: 287559 + 801 = 288360
Step 361: 288360 + 801 = 289161
Step 362: 289161 + 801 = 289962
Step 363: 289962 + 801 = 290763
Step 364: 290763 + 801 = 291564
Step 365: 291564 + 801 = 292365
Step 366: 292365 + 801 = 293166
Step 367: 293166 + 801 = 293967
Step 368: 293967 + 801 = 294768
Step 369: 294768 + 801 = 295569
Step 370: 295569 + 801 = 296370
Step 371: 296370 + 801 = 297171
Step 372: 297171 + 801 = 297972
Step 373: 297972 + 801 = 298773
Step 374: 298773 + 801 = 299574
Step 375: 299574 + 801 = 300375
Step 376: 300375 + 801 = 301176
Step 377: 301176 + 801 = 301977
Step 378: 301977 + 801 = 302778
Step 379: 302778 + 801 = 303579
Step 380: 303579 + 801 = 304380
Step 381: 304380 + 801 = 305181
Step 382: 305181 + 801 = 305982
Step 383: 305982 + 801 = 306783
Step 384: 306783 + 801 = 307584
Step 385: 307584 + 801 = 308385
Step 386: 308385 + 801 = 309186
Step 387: 309186 + 801 = 309987
Step 388: 309987 + 801 = 310788
Step 389: 310788 + 801 = 311589
Step 390: 311589 + 801 = 312390
Step 391: 312390 + 801 = 313191
Step 392: 313191 + 801 = 313992
Step 393: 313992 + 801 = 314793
Step 394: 314793 + 801 = 315594
Step 395: 315594 + 801 = 316395
Step 396: 316395 + 801 = 317196
Step 397: 317196 + 801 = 317997
Step 398: 317997 + 801 = 318798
Step 399: 318798 + 801 = 319599
Step 400: 319599 + 801 = 320400
Step 401: 320400 + 801 = 321201
Step 402: 321201 + 801 = 322002
Step 403: 322002 + 801 = 322803
Step 404: 322803 + 801 = 323604
Step 405: 323604 + 801 = 324405
Step 406: 324405 + 801 = 325206
Step 407: 325206 + 801 = 326007
Step 408: 326007 + 801 = 326808
Step 409: 326808 + 801 = 327609
Step 410: 327609 + 801 = 328410
Step 411: 328410 + 801 = 329211
Step 412: 329211 + 801 = 330012
Step 413: 330012 + 801 = 330813
Step 414: 330813 + 801 = 331614
Step 415: 331614 + 801 = 332415
Step 416: 332415 + 801 = 333216
Step 417: 333216 + 801 = 334017
Step 418: 334017 + 801 = 334818
Step 419: 334818 + 801 = 335619
Step 420: 335619 + 801 = 336420

So, 801*420 = 336420