OK, let's work through this together. We're starting with 457 and we're going to multiply it by 90, which means we add 457 to itself 90 times.
Step 1: 0 + 457 = 457
Step 2: 457 + 457 = 914
Step 3: 914 + 457 = 1371
Step 4: 1371 + 457 = 1828
Step 5: 1828 + 457 = 2285
Step 6: 2285 + 457 = 2742
Step 7: 2742 + 457 = 3199
Step 8: 3199 + 457 = 3656
Step 9: 3656 + 457 = 4113
Step 10: 4113 + 457 = 4570
Step 11: 4570 + 457 = 5027
Step 12: 5027 + 457 = 5484
Step 13: 5484 + 457 = 5941
Step 14: 5941 + 457 = 6398
Step 15: 6398 + 457 = 6855
Step 16: 6855 + 457 = 7312
Step 17: 7312 + 457 = 7769
Step 18: 7769 + 457 = 8226
Step 19: 8226 + 457 = 8683
Step 20: 8683 + 457 = 9140
Step 21: 9140 + 457 = 9597
Step 22: 9597 + 457 = 10054
Step 23: 10054 + 457 = 10511
Step 24: 10511 + 457 = 10968
Step 25: 10968 + 457 = 11425
Step 26: 11425 + 457 = 11882
Step 27: 11882 + 457 = 12339
Step 28: 12339 + 457 = 12796
Step 29: 12796 + 457 = 13253
Step 30: 13253 + 457 = 13710
Step 31: 13710 + 457 = 14167
Step 32: 14167 + 457 = 14624
Step 33: 14624 + 457 = 15081
Step 34: 15081 + 457 = 15538
Step 35: 15538 + 457 = 15995
Step 36: 15995 + 457 = 16452
Step 37: 16452 + 457 = 16909
Step 38: 16909 + 457 = 17366
Step 39: 17366 + 457 = 17823
Step 40: 17823 + 457 = 18280
Step 41: 18280 + 457 = 18737
Step 42: 18737 + 457 = 19194
Step 43: 19194 + 457 = 19651
Step 44: 19651 + 457 = 20108
Step 45: 20108 + 457 = 20565
Step 46: 20565 + 457 = 21022
Step 47: 21022 + 457 = 21479
Step 48: 21479 + 457 = 21936
Step 49: 21936 + 457 = 22393
Step 50: 22393 + 457 = 22850
Step 51: 22850 + 457 = 23307
Step 52: 23307 + 457 = 23764
Step 53: 23764 + 457 = 24221
Step 54: 24221 + 457 = 24678
Step 55: 24678 + 457 = 25135
Step 56: 25135 + 457 = 25592
Step 57: 25592 + 457 = 26049
Step 58: 26049 + 457 = 26506
Step 59: 26506 + 457 = 26963
Step 60: 26963 + 457 = 27420
Step 61: 27420 + 457 = 27877
Step 62: 27877 + 457 = 28334
Step 63: 28334 + 457 = 28791
Step 64: 28791 + 457 = 29248
Step 65: 29248 + 457 = 29705
Step 66: 29705 + 457 = 30162
Step 67: 30162 + 457 = 30619
Step 68: 30619 + 457 = 31076
Step 69: 31076 + 457 = 31533
Step 70: 31533 + 457 = 31990
Step 71: 31990 + 457 = 32447
Step 72: 32447 + 457 = 32904
Step 73: 32904 + 457 = 33361
Step 74: 33361 + 457 = 33818
Step 75: 33818 + 457 = 34275
Step 76: 34275 + 457 = 34732
Step 77: 34732 + 457 = 35189
Step 78: 35189 + 457 = 35646
Step 79: 35646 + 457 = 36103
Step 80: 36103 + 457 = 36560
Step 81: 36560 + 457 = 37017
Step 82: 37017 + 457 = 37474
Step 83: 37474 + 457 = 37931
Step 84: 37931 + 457 = 38388
Step 85: 38388 + 457 = 38845
Step 86: 38845 + 457 = 39302
Step 87: 39302 + 457 = 39759
Step 88: 39759 + 457 = 40216
Step 89: 40216 + 457 = 40673
Step 90: 40673 + 457 = 41130

So, 457*90 = 41130