OK, let's work through this together. We're starting with 787 and we're going to multiply it by 154, which means we add 787 to itself 154 times.
Step 1: 0 + 787 = 787
Step 2: 787 + 787 = 1574
Step 3: 1574 + 787 = 2361
Step 4: 2361 + 787 = 3148
Step 5: 3148 + 787 = 3935
Step 6: 3935 + 787 = 4722
Step 7: 4722 + 787 = 5509
Step 8: 5509 + 787 = 6296
Step 9: 6296 + 787 = 7083
Step 10: 7083 + 787 = 7870
Step 11: 7870 + 787 = 8657
Step 12: 8657 + 787 = 9444
Step 13: 9444 + 787 = 10231
Step 14: 10231 + 787 = 11018
Step 15: 11018 + 787 = 11805
Step 16: 11805 + 787 = 12592
Step 17: 12592 + 787 = 13379
Step 18: 13379 + 787 = 14166
Step 19: 14166 + 787 = 14953
Step 20: 14953 + 787 = 15740
Step 21: 15740 + 787 = 16527
Step 22: 16527 + 787 = 17314
Step 23: 17314 + 787 = 18101
Step 24: 18101 + 787 = 18888
Step 25: 18888 + 787 = 19675
Step 26: 19675 + 787 = 20462
Step 27: 20462 + 787 = 21249
Step 28: 21249 + 787 = 22036
Step 29: 22036 + 787 = 22823
Step 30: 22823 + 787 = 23610
Step 31: 23610 + 787 = 24397
Step 32: 24397 + 787 = 25184
Step 33: 25184 + 787 = 25971
Step 34: 25971 + 787 = 26758
Step 35: 26758 + 787 = 27545
Step 36: 27545 + 787 = 28332
Step 37: 28332 + 787 = 29119
Step 38: 29119 + 787 = 29906
Step 39: 29906 + 787 = 30693
Step 40: 30693 + 787 = 31480
Step 41: 31480 + 787 = 32267
Step 42: 32267 + 787 = 33054
Step 43: 33054 + 787 = 33841
Step 44: 33841 + 787 = 34628
Step 45: 34628 + 787 = 35415
Step 46: 35415 + 787 = 36202
Step 47: 36202 + 787 = 36989
Step 48: 36989 + 787 = 37776
Step 49: 37776 + 787 = 38563
Step 50: 38563 + 787 = 39350
Step 51: 39350 + 787 = 40137
Step 52: 40137 + 787 = 40924
Step 53: 40924 + 787 = 41711
Step 54: 41711 + 787 = 42498
Step 55: 42498 + 787 = 43285
Step 56: 43285 + 787 = 44072
Step 57: 44072 + 787 = 44859
Step 58: 44859 + 787 = 45646
Step 59: 45646 + 787 = 46433
Step 60: 46433 + 787 = 47220
Step 61: 47220 + 787 = 48007
Step 62: 48007 + 787 = 48794
Step 63: 48794 + 787 = 49581
Step 64: 49581 + 787 = 50368
Step 65: 50368 + 787 = 51155
Step 66: 51155 + 787 = 51942
Step 67: 51942 + 787 = 52729
Step 68: 52729 + 787 = 53516
Step 69: 53516 + 787 = 54303
Step 70: 54303 + 787 = 55090
Step 71: 55090 + 787 = 55877
Step 72: 55877 + 787 = 56664
Step 73: 56664 + 787 = 57451
Step 74: 57451 + 787 = 58238
Step 75: 58238 + 787 = 59025
Step 76: 59025 + 787 = 59812
Step 77: 59812 + 787 = 60599
Step 78: 60599 + 787 = 61386
Step 79: 61386 + 787 = 62173
Step 80: 62173 + 787 = 62960
Step 81: 62960 + 787 = 63747
Step 82: 63747 + 787 = 64534
Step 83: 64534 + 787 = 65321
Step 84: 65321 + 787 = 66108
Step 85: 66108 + 787 = 66895
Step 86: 66895 + 787 = 67682
Step 87: 67682 + 787 = 68469
Step 88: 68469 + 787 = 69256
Step 89: 69256 + 787 = 70043
Step 90: 70043 + 787 = 70830
Step 91: 70830 + 787 = 71617
Step 92: 71617 + 787 = 72404
Step 93: 72404 + 787 = 73191
Step 94: 73191 + 787 = 73978
Step 95: 73978 + 787 = 74765
Step 96: 74765 + 787 = 75552
Step 97: 75552 + 787 = 76339
Step 98: 76339 + 787 = 77126
Step 99: 77126 + 787 = 77913
Step 100: 77913 + 787 = 78700
Step 101: 78700 + 787 = 79487
Step 102: 79487 + 787 = 80274
Step 103: 80274 + 787 = 81061
Step 104: 81061 + 787 = 81848
Step 105: 81848 + 787 = 82635
Step 106: 82635 + 787 = 83422
Step 107: 83422 + 787 = 84209
Step 108: 84209 + 787 = 84996
Step 109: 84996 + 787 = 85783
Step 110: 85783 + 787 = 86570
Step 111: 86570 + 787 = 87357
Step 112: 87357 + 787 = 88144
Step 113: 88144 + 787 = 88931
Step 114: 88931 + 787 = 89718
Step 115: 89718 + 787 = 90505
Step 116: 90505 + 787 = 91292
Step 117: 91292 + 787 = 92079
Step 118: 92079 + 787 = 92866
Step 119: 92866 + 787 = 93653
Step 120: 93653 + 787 = 94440
Step 121: 94440 + 787 = 95227
Step 122: 95227 + 787 = 96014
Step 123: 96014 + 787 = 96801
Step 124: 96801 + 787 = 97588
Step 125: 97588 + 787 = 98375
Step 126: 98375 + 787 = 99162
Step 127: 99162 + 787 = 99949
Step 128: 99949 + 787 = 100736
Step 129: 100736 + 787 = 101523
Step 130: 101523 + 787 = 102310
Step 131: 102310 + 787 = 103097
Step 132: 103097 + 787 = 103884
Step 133: 103884 + 787 = 104671
Step 134: 104671 + 787 = 105458
Step 135: 105458 + 787 = 106245
Step 136: 106245 + 787 = 107032
Step 137: 107032 + 787 = 107819
Step 138: 107819 + 787 = 108606
Step 139: 108606 + 787 = 109393
Step 140: 109393 + 787 = 110180
Step 141: 110180 + 787 = 110967
Step 142: 110967 + 787 = 111754
Step 143: 111754 + 787 = 112541
Step 144: 112541 + 787 = 113328
Step 145: 113328 + 787 = 114115
Step 146: 114115 + 787 = 114902
Step 147: 114902 + 787 = 115689
Step 148: 115689 + 787 = 116476
Step 149: 116476 + 787 = 117263
Step 150: 117263 + 787 = 118050
Step 151: 118050 + 787 = 118837
Step 152: 118837 + 787 = 119624
Step 153: 119624 + 787 = 120411
Step 154: 120411 + 787 = 121198

So, 787*154 = 121198