Without delay, let's solve this. We've got 842 and we will be multiplying it by 158, that is, adding 842 to itself 158 times.
Step 1: 0 + 842 = 842
Step 2: 842 + 842 = 1684
Step 3: 1684 + 842 = 2526
Step 4: 2526 + 842 = 3368
Step 5: 3368 + 842 = 4210
Step 6: 4210 + 842 = 5052
Step 7: 5052 + 842 = 5894
Step 8: 5894 + 842 = 6736
Step 9: 6736 + 842 = 7578
Step 10: 7578 + 842 = 8420
Step 11: 8420 + 842 = 9262
Step 12: 9262 + 842 = 10104
Step 13: 10104 + 842 = 10946
Step 14: 10946 + 842 = 11788
Step 15: 11788 + 842 = 12630
Step 16: 12630 + 842 = 13472
Step 17: 13472 + 842 = 14314
Step 18: 14314 + 842 = 15156
Step 19: 15156 + 842 = 15998
Step 20: 15998 + 842 = 16840
Step 21: 16840 + 842 = 17682
Step 22: 17682 + 842 = 18524
Step 23: 18524 + 842 = 19366
Step 24: 19366 + 842 = 20208
Step 25: 20208 + 842 = 21050
Step 26: 21050 + 842 = 21892
Step 27: 21892 + 842 = 22734
Step 28: 22734 + 842 = 23576
Step 29: 23576 + 842 = 24418
Step 30: 24418 + 842 = 25260
Step 31: 25260 + 842 = 26102
Step 32: 26102 + 842 = 26944
Step 33: 26944 + 842 = 27786
Step 34: 27786 + 842 = 28628
Step 35: 28628 + 842 = 29470
Step 36: 29470 + 842 = 30312
Step 37: 30312 + 842 = 31154
Step 38: 31154 + 842 = 31996
Step 39: 31996 + 842 = 32838
Step 40: 32838 + 842 = 33680
Step 41: 33680 + 842 = 34522
Step 42: 34522 + 842 = 35364
Step 43: 35364 + 842 = 36206
Step 44: 36206 + 842 = 37048
Step 45: 37048 + 842 = 37890
Step 46: 37890 + 842 = 38732
Step 47: 38732 + 842 = 39574
Step 48: 39574 + 842 = 40416
Step 49: 40416 + 842 = 41258
Step 50: 41258 + 842 = 42100
Step 51: 42100 + 842 = 42942
Step 52: 42942 + 842 = 43784
Step 53: 43784 + 842 = 44626
Step 54: 44626 + 842 = 45468
Step 55: 45468 + 842 = 46310
Step 56: 46310 + 842 = 47152
Step 57: 47152 + 842 = 47994
Step 58: 47994 + 842 = 48836
Step 59: 48836 + 842 = 49678
Step 60: 49678 + 842 = 50520
Step 61: 50520 + 842 = 51362
Step 62: 51362 + 842 = 52204
Step 63: 52204 + 842 = 53046
Step 64: 53046 + 842 = 53888
Step 65: 53888 + 842 = 54730
Step 66: 54730 + 842 = 55572
Step 67: 55572 + 842 = 56414
Step 68: 56414 + 842 = 57256
Step 69: 57256 + 842 = 58098
Step 70: 58098 + 842 = 58940
Step 71: 58940 + 842 = 59782
Step 72: 59782 + 842 = 60624
Step 73: 60624 + 842 = 61466
Step 74: 61466 + 842 = 62308
Step 75: 62308 + 842 = 63150
Step 76: 63150 + 842 = 63992
Step 77: 63992 + 842 = 64834
Step 78: 64834 + 842 = 65676
Step 79: 65676 + 842 = 66518
Step 80: 66518 + 842 = 67360
Step 81: 67360 + 842 = 68202
Step 82: 68202 + 842 = 69044
Step 83: 69044 + 842 = 69886
Step 84: 69886 + 842 = 70728
Step 85: 70728 + 842 = 71570
Step 86: 71570 + 842 = 72412
Step 87: 72412 + 842 = 73254
Step 88: 73254 + 842 = 74096
Step 89: 74096 + 842 = 74938
Step 90: 74938 + 842 = 75780
Step 91: 75780 + 842 = 76622
Step 92: 76622 + 842 = 77464
Step 93: 77464 + 842 = 78306
Step 94: 78306 + 842 = 79148
Step 95: 79148 + 842 = 79990
Step 96: 79990 + 842 = 80832
Step 97: 80832 + 842 = 81674
Step 98: 81674 + 842 = 82516
Step 99: 82516 + 842 = 83358
Step 100: 83358 + 842 = 84200
Step 101: 84200 + 842 = 85042
Step 102: 85042 + 842 = 85884
Step 103: 85884 + 842 = 86726
Step 104: 86726 + 842 = 87568
Step 105: 87568 + 842 = 88410
Step 106: 88410 + 842 = 89252
Step 107: 89252 + 842 = 90094
Step 108: 90094 + 842 = 90936
Step 109: 90936 + 842 = 91778
Step 110: 91778 + 842 = 92620
Step 111: 92620 + 842 = 93462
Step 112: 93462 + 842 = 94304
Step 113: 94304 + 842 = 95146
Step 114: 95146 + 842 = 95988
Step 115: 95988 + 842 = 96830
Step 116: 96830 + 842 = 97672
Step 117: 97672 + 842 = 98514
Step 118: 98514 + 842 = 99356
Step 119: 99356 + 842 = 100198
Step 120: 100198 + 842 = 101040
Step 121: 101040 + 842 = 101882
Step 122: 101882 + 842 = 102724
Step 123: 102724 + 842 = 103566
Step 124: 103566 + 842 = 104408
Step 125: 104408 + 842 = 105250
Step 126: 105250 + 842 = 106092
Step 127: 106092 + 842 = 106934
Step 128: 106934 + 842 = 107776
Step 129: 107776 + 842 = 108618
Step 130: 108618 + 842 = 109460
Step 131: 109460 + 842 = 110302
Step 132: 110302 + 842 = 111144
Step 133: 111144 + 842 = 111986
Step 134: 111986 + 842 = 112828
Step 135: 112828 + 842 = 113670
Step 136: 113670 + 842 = 114512
Step 137: 114512 + 842 = 115354
Step 138: 115354 + 842 = 116196
Step 139: 116196 + 842 = 117038
Step 140: 117038 + 842 = 117880
Step 141: 117880 + 842 = 118722
Step 142: 118722 + 842 = 119564
Step 143: 119564 + 842 = 120406
Step 144: 120406 + 842 = 121248
Step 145: 121248 + 842 = 122090
Step 146: 122090 + 842 = 122932
Step 147: 122932 + 842 = 123774
Step 148: 123774 + 842 = 124616
Step 149: 124616 + 842 = 125458
Step 150: 125458 + 842 = 126300
Step 151: 126300 + 842 = 127142
Step 152: 127142 + 842 = 127984
Step 153: 127984 + 842 = 128826
Step 154: 128826 + 842 = 129668
Step 155: 129668 + 842 = 130510
Step 156: 130510 + 842 = 131352
Step 157: 131352 + 842 = 132194
Step 158: 132194 + 842 = 133036

So, 842*158 = 133036