Alright, let's solve this math problem step by step. First, we have the number 142. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 149. So, we're going to take the number 142 and add it to itself 149 times.
Step 1: 0 + 142 = 142
Step 2: 142 + 142 = 284
Step 3: 284 + 142 = 426
Step 4: 426 + 142 = 568
Step 5: 568 + 142 = 710
Step 6: 710 + 142 = 852
Step 7: 852 + 142 = 994
Step 8: 994 + 142 = 1136
Step 9: 1136 + 142 = 1278
Step 10: 1278 + 142 = 1420
Step 11: 1420 + 142 = 1562
Step 12: 1562 + 142 = 1704
Step 13: 1704 + 142 = 1846
Step 14: 1846 + 142 = 1988
Step 15: 1988 + 142 = 2130
Step 16: 2130 + 142 = 2272
Step 17: 2272 + 142 = 2414
Step 18: 2414 + 142 = 2556
Step 19: 2556 + 142 = 2698
Step 20: 2698 + 142 = 2840
Step 21: 2840 + 142 = 2982
Step 22: 2982 + 142 = 3124
Step 23: 3124 + 142 = 3266
Step 24: 3266 + 142 = 3408
Step 25: 3408 + 142 = 3550
Step 26: 3550 + 142 = 3692
Step 27: 3692 + 142 = 3834
Step 28: 3834 + 142 = 3976
Step 29: 3976 + 142 = 4118
Step 30: 4118 + 142 = 4260
Step 31: 4260 + 142 = 4402
Step 32: 4402 + 142 = 4544
Step 33: 4544 + 142 = 4686
Step 34: 4686 + 142 = 4828
Step 35: 4828 + 142 = 4970
Step 36: 4970 + 142 = 5112
Step 37: 5112 + 142 = 5254
Step 38: 5254 + 142 = 5396
Step 39: 5396 + 142 = 5538
Step 40: 5538 + 142 = 5680
Step 41: 5680 + 142 = 5822
Step 42: 5822 + 142 = 5964
Step 43: 5964 + 142 = 6106
Step 44: 6106 + 142 = 6248
Step 45: 6248 + 142 = 6390
Step 46: 6390 + 142 = 6532
Step 47: 6532 + 142 = 6674
Step 48: 6674 + 142 = 6816
Step 49: 6816 + 142 = 6958
Step 50: 6958 + 142 = 7100
Step 51: 7100 + 142 = 7242
Step 52: 7242 + 142 = 7384
Step 53: 7384 + 142 = 7526
Step 54: 7526 + 142 = 7668
Step 55: 7668 + 142 = 7810
Step 56: 7810 + 142 = 7952
Step 57: 7952 + 142 = 8094
Step 58: 8094 + 142 = 8236
Step 59: 8236 + 142 = 8378
Step 60: 8378 + 142 = 8520
Step 61: 8520 + 142 = 8662
Step 62: 8662 + 142 = 8804
Step 63: 8804 + 142 = 8946
Step 64: 8946 + 142 = 9088
Step 65: 9088 + 142 = 9230
Step 66: 9230 + 142 = 9372
Step 67: 9372 + 142 = 9514
Step 68: 9514 + 142 = 9656
Step 69: 9656 + 142 = 9798
Step 70: 9798 + 142 = 9940
Step 71: 9940 + 142 = 10082
Step 72: 10082 + 142 = 10224
Step 73: 10224 + 142 = 10366
Step 74: 10366 + 142 = 10508
Step 75: 10508 + 142 = 10650
Step 76: 10650 + 142 = 10792
Step 77: 10792 + 142 = 10934
Step 78: 10934 + 142 = 11076
Step 79: 11076 + 142 = 11218
Step 80: 11218 + 142 = 11360
Step 81: 11360 + 142 = 11502
Step 82: 11502 + 142 = 11644
Step 83: 11644 + 142 = 11786
Step 84: 11786 + 142 = 11928
Step 85: 11928 + 142 = 12070
Step 86: 12070 + 142 = 12212
Step 87: 12212 + 142 = 12354
Step 88: 12354 + 142 = 12496
Step 89: 12496 + 142 = 12638
Step 90: 12638 + 142 = 12780
Step 91: 12780 + 142 = 12922
Step 92: 12922 + 142 = 13064
Step 93: 13064 + 142 = 13206
Step 94: 13206 + 142 = 13348
Step 95: 13348 + 142 = 13490
Step 96: 13490 + 142 = 13632
Step 97: 13632 + 142 = 13774
Step 98: 13774 + 142 = 13916
Step 99: 13916 + 142 = 14058
Step 100: 14058 + 142 = 14200
Step 101: 14200 + 142 = 14342
Step 102: 14342 + 142 = 14484
Step 103: 14484 + 142 = 14626
Step 104: 14626 + 142 = 14768
Step 105: 14768 + 142 = 14910
Step 106: 14910 + 142 = 15052
Step 107: 15052 + 142 = 15194
Step 108: 15194 + 142 = 15336
Step 109: 15336 + 142 = 15478
Step 110: 15478 + 142 = 15620
Step 111: 15620 + 142 = 15762
Step 112: 15762 + 142 = 15904
Step 113: 15904 + 142 = 16046
Step 114: 16046 + 142 = 16188
Step 115: 16188 + 142 = 16330
Step 116: 16330 + 142 = 16472
Step 117: 16472 + 142 = 16614
Step 118: 16614 + 142 = 16756
Step 119: 16756 + 142 = 16898
Step 120: 16898 + 142 = 17040
Step 121: 17040 + 142 = 17182
Step 122: 17182 + 142 = 17324
Step 123: 17324 + 142 = 17466
Step 124: 17466 + 142 = 17608
Step 125: 17608 + 142 = 17750
Step 126: 17750 + 142 = 17892
Step 127: 17892 + 142 = 18034
Step 128: 18034 + 142 = 18176
Step 129: 18176 + 142 = 18318
Step 130: 18318 + 142 = 18460
Step 131: 18460 + 142 = 18602
Step 132: 18602 + 142 = 18744
Step 133: 18744 + 142 = 18886
Step 134: 18886 + 142 = 19028
Step 135: 19028 + 142 = 19170
Step 136: 19170 + 142 = 19312
Step 137: 19312 + 142 = 19454
Step 138: 19454 + 142 = 19596
Step 139: 19596 + 142 = 19738
Step 140: 19738 + 142 = 19880
Step 141: 19880 + 142 = 20022
Step 142: 20022 + 142 = 20164
Step 143: 20164 + 142 = 20306
Step 144: 20306 + 142 = 20448
Step 145: 20448 + 142 = 20590
Step 146: 20590 + 142 = 20732
Step 147: 20732 + 142 = 20874
Step 148: 20874 + 142 = 21016
Step 149: 21016 + 142 = 21158

So, 142*149 = 21158