Alright, let's solve this math problem step by step. First, we have the number 642. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 154. So, we're going to take the number 642 and add it to itself 154 times.
Step 1: 0 + 642 = 642
Step 2: 642 + 642 = 1284
Step 3: 1284 + 642 = 1926
Step 4: 1926 + 642 = 2568
Step 5: 2568 + 642 = 3210
Step 6: 3210 + 642 = 3852
Step 7: 3852 + 642 = 4494
Step 8: 4494 + 642 = 5136
Step 9: 5136 + 642 = 5778
Step 10: 5778 + 642 = 6420
Step 11: 6420 + 642 = 7062
Step 12: 7062 + 642 = 7704
Step 13: 7704 + 642 = 8346
Step 14: 8346 + 642 = 8988
Step 15: 8988 + 642 = 9630
Step 16: 9630 + 642 = 10272
Step 17: 10272 + 642 = 10914
Step 18: 10914 + 642 = 11556
Step 19: 11556 + 642 = 12198
Step 20: 12198 + 642 = 12840
Step 21: 12840 + 642 = 13482
Step 22: 13482 + 642 = 14124
Step 23: 14124 + 642 = 14766
Step 24: 14766 + 642 = 15408
Step 25: 15408 + 642 = 16050
Step 26: 16050 + 642 = 16692
Step 27: 16692 + 642 = 17334
Step 28: 17334 + 642 = 17976
Step 29: 17976 + 642 = 18618
Step 30: 18618 + 642 = 19260
Step 31: 19260 + 642 = 19902
Step 32: 19902 + 642 = 20544
Step 33: 20544 + 642 = 21186
Step 34: 21186 + 642 = 21828
Step 35: 21828 + 642 = 22470
Step 36: 22470 + 642 = 23112
Step 37: 23112 + 642 = 23754
Step 38: 23754 + 642 = 24396
Step 39: 24396 + 642 = 25038
Step 40: 25038 + 642 = 25680
Step 41: 25680 + 642 = 26322
Step 42: 26322 + 642 = 26964
Step 43: 26964 + 642 = 27606
Step 44: 27606 + 642 = 28248
Step 45: 28248 + 642 = 28890
Step 46: 28890 + 642 = 29532
Step 47: 29532 + 642 = 30174
Step 48: 30174 + 642 = 30816
Step 49: 30816 + 642 = 31458
Step 50: 31458 + 642 = 32100
Step 51: 32100 + 642 = 32742
Step 52: 32742 + 642 = 33384
Step 53: 33384 + 642 = 34026
Step 54: 34026 + 642 = 34668
Step 55: 34668 + 642 = 35310
Step 56: 35310 + 642 = 35952
Step 57: 35952 + 642 = 36594
Step 58: 36594 + 642 = 37236
Step 59: 37236 + 642 = 37878
Step 60: 37878 + 642 = 38520
Step 61: 38520 + 642 = 39162
Step 62: 39162 + 642 = 39804
Step 63: 39804 + 642 = 40446
Step 64: 40446 + 642 = 41088
Step 65: 41088 + 642 = 41730
Step 66: 41730 + 642 = 42372
Step 67: 42372 + 642 = 43014
Step 68: 43014 + 642 = 43656
Step 69: 43656 + 642 = 44298
Step 70: 44298 + 642 = 44940
Step 71: 44940 + 642 = 45582
Step 72: 45582 + 642 = 46224
Step 73: 46224 + 642 = 46866
Step 74: 46866 + 642 = 47508
Step 75: 47508 + 642 = 48150
Step 76: 48150 + 642 = 48792
Step 77: 48792 + 642 = 49434
Step 78: 49434 + 642 = 50076
Step 79: 50076 + 642 = 50718
Step 80: 50718 + 642 = 51360
Step 81: 51360 + 642 = 52002
Step 82: 52002 + 642 = 52644
Step 83: 52644 + 642 = 53286
Step 84: 53286 + 642 = 53928
Step 85: 53928 + 642 = 54570
Step 86: 54570 + 642 = 55212
Step 87: 55212 + 642 = 55854
Step 88: 55854 + 642 = 56496
Step 89: 56496 + 642 = 57138
Step 90: 57138 + 642 = 57780
Step 91: 57780 + 642 = 58422
Step 92: 58422 + 642 = 59064
Step 93: 59064 + 642 = 59706
Step 94: 59706 + 642 = 60348
Step 95: 60348 + 642 = 60990
Step 96: 60990 + 642 = 61632
Step 97: 61632 + 642 = 62274
Step 98: 62274 + 642 = 62916
Step 99: 62916 + 642 = 63558
Step 100: 63558 + 642 = 64200
Step 101: 64200 + 642 = 64842
Step 102: 64842 + 642 = 65484
Step 103: 65484 + 642 = 66126
Step 104: 66126 + 642 = 66768
Step 105: 66768 + 642 = 67410
Step 106: 67410 + 642 = 68052
Step 107: 68052 + 642 = 68694
Step 108: 68694 + 642 = 69336
Step 109: 69336 + 642 = 69978
Step 110: 69978 + 642 = 70620
Step 111: 70620 + 642 = 71262
Step 112: 71262 + 642 = 71904
Step 113: 71904 + 642 = 72546
Step 114: 72546 + 642 = 73188
Step 115: 73188 + 642 = 73830
Step 116: 73830 + 642 = 74472
Step 117: 74472 + 642 = 75114
Step 118: 75114 + 642 = 75756
Step 119: 75756 + 642 = 76398
Step 120: 76398 + 642 = 77040
Step 121: 77040 + 642 = 77682
Step 122: 77682 + 642 = 78324
Step 123: 78324 + 642 = 78966
Step 124: 78966 + 642 = 79608
Step 125: 79608 + 642 = 80250
Step 126: 80250 + 642 = 80892
Step 127: 80892 + 642 = 81534
Step 128: 81534 + 642 = 82176
Step 129: 82176 + 642 = 82818
Step 130: 82818 + 642 = 83460
Step 131: 83460 + 642 = 84102
Step 132: 84102 + 642 = 84744
Step 133: 84744 + 642 = 85386
Step 134: 85386 + 642 = 86028
Step 135: 86028 + 642 = 86670
Step 136: 86670 + 642 = 87312
Step 137: 87312 + 642 = 87954
Step 138: 87954 + 642 = 88596
Step 139: 88596 + 642 = 89238
Step 140: 89238 + 642 = 89880
Step 141: 89880 + 642 = 90522
Step 142: 90522 + 642 = 91164
Step 143: 91164 + 642 = 91806
Step 144: 91806 + 642 = 92448
Step 145: 92448 + 642 = 93090
Step 146: 93090 + 642 = 93732
Step 147: 93732 + 642 = 94374
Step 148: 94374 + 642 = 95016
Step 149: 95016 + 642 = 95658
Step 150: 95658 + 642 = 96300
Step 151: 96300 + 642 = 96942
Step 152: 96942 + 642 = 97584
Step 153: 97584 + 642 = 98226
Step 154: 98226 + 642 = 98868

So, 642*154 = 98868