Let's get this math done. We have 421 and we're going to multiply it by 89. This is the same as taking 421 and adding it to itself 89 times.
Step 1: 0 + 421 = 421
Step 2: 421 + 421 = 842
Step 3: 842 + 421 = 1263
Step 4: 1263 + 421 = 1684
Step 5: 1684 + 421 = 2105
Step 6: 2105 + 421 = 2526
Step 7: 2526 + 421 = 2947
Step 8: 2947 + 421 = 3368
Step 9: 3368 + 421 = 3789
Step 10: 3789 + 421 = 4210
Step 11: 4210 + 421 = 4631
Step 12: 4631 + 421 = 5052
Step 13: 5052 + 421 = 5473
Step 14: 5473 + 421 = 5894
Step 15: 5894 + 421 = 6315
Step 16: 6315 + 421 = 6736
Step 17: 6736 + 421 = 7157
Step 18: 7157 + 421 = 7578
Step 19: 7578 + 421 = 7999
Step 20: 7999 + 421 = 8420
Step 21: 8420 + 421 = 8841
Step 22: 8841 + 421 = 9262
Step 23: 9262 + 421 = 9683
Step 24: 9683 + 421 = 10104
Step 25: 10104 + 421 = 10525
Step 26: 10525 + 421 = 10946
Step 27: 10946 + 421 = 11367
Step 28: 11367 + 421 = 11788
Step 29: 11788 + 421 = 12209
Step 30: 12209 + 421 = 12630
Step 31: 12630 + 421 = 13051
Step 32: 13051 + 421 = 13472
Step 33: 13472 + 421 = 13893
Step 34: 13893 + 421 = 14314
Step 35: 14314 + 421 = 14735
Step 36: 14735 + 421 = 15156
Step 37: 15156 + 421 = 15577
Step 38: 15577 + 421 = 15998
Step 39: 15998 + 421 = 16419
Step 40: 16419 + 421 = 16840
Step 41: 16840 + 421 = 17261
Step 42: 17261 + 421 = 17682
Step 43: 17682 + 421 = 18103
Step 44: 18103 + 421 = 18524
Step 45: 18524 + 421 = 18945
Step 46: 18945 + 421 = 19366
Step 47: 19366 + 421 = 19787
Step 48: 19787 + 421 = 20208
Step 49: 20208 + 421 = 20629
Step 50: 20629 + 421 = 21050
Step 51: 21050 + 421 = 21471
Step 52: 21471 + 421 = 21892
Step 53: 21892 + 421 = 22313
Step 54: 22313 + 421 = 22734
Step 55: 22734 + 421 = 23155
Step 56: 23155 + 421 = 23576
Step 57: 23576 + 421 = 23997
Step 58: 23997 + 421 = 24418
Step 59: 24418 + 421 = 24839
Step 60: 24839 + 421 = 25260
Step 61: 25260 + 421 = 25681
Step 62: 25681 + 421 = 26102
Step 63: 26102 + 421 = 26523
Step 64: 26523 + 421 = 26944
Step 65: 26944 + 421 = 27365
Step 66: 27365 + 421 = 27786
Step 67: 27786 + 421 = 28207
Step 68: 28207 + 421 = 28628
Step 69: 28628 + 421 = 29049
Step 70: 29049 + 421 = 29470
Step 71: 29470 + 421 = 29891
Step 72: 29891 + 421 = 30312
Step 73: 30312 + 421 = 30733
Step 74: 30733 + 421 = 31154
Step 75: 31154 + 421 = 31575
Step 76: 31575 + 421 = 31996
Step 77: 31996 + 421 = 32417
Step 78: 32417 + 421 = 32838
Step 79: 32838 + 421 = 33259
Step 80: 33259 + 421 = 33680
Step 81: 33680 + 421 = 34101
Step 82: 34101 + 421 = 34522
Step 83: 34522 + 421 = 34943
Step 84: 34943 + 421 = 35364
Step 85: 35364 + 421 = 35785
Step 86: 35785 + 421 = 36206
Step 87: 36206 + 421 = 36627
Step 88: 36627 + 421 = 37048
Step 89: 37048 + 421 = 37469

So, 421*89 = 37469