Alright, let's solve this math problem step by step. First, we have the number 873. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 139. So, we're going to take the number 873 and add it to itself 139 times.
Step 1: 0 + 873 = 873
Step 2: 873 + 873 = 1746
Step 3: 1746 + 873 = 2619
Step 4: 2619 + 873 = 3492
Step 5: 3492 + 873 = 4365
Step 6: 4365 + 873 = 5238
Step 7: 5238 + 873 = 6111
Step 8: 6111 + 873 = 6984
Step 9: 6984 + 873 = 7857
Step 10: 7857 + 873 = 8730
Step 11: 8730 + 873 = 9603
Step 12: 9603 + 873 = 10476
Step 13: 10476 + 873 = 11349
Step 14: 11349 + 873 = 12222
Step 15: 12222 + 873 = 13095
Step 16: 13095 + 873 = 13968
Step 17: 13968 + 873 = 14841
Step 18: 14841 + 873 = 15714
Step 19: 15714 + 873 = 16587
Step 20: 16587 + 873 = 17460
Step 21: 17460 + 873 = 18333
Step 22: 18333 + 873 = 19206
Step 23: 19206 + 873 = 20079
Step 24: 20079 + 873 = 20952
Step 25: 20952 + 873 = 21825
Step 26: 21825 + 873 = 22698
Step 27: 22698 + 873 = 23571
Step 28: 23571 + 873 = 24444
Step 29: 24444 + 873 = 25317
Step 30: 25317 + 873 = 26190
Step 31: 26190 + 873 = 27063
Step 32: 27063 + 873 = 27936
Step 33: 27936 + 873 = 28809
Step 34: 28809 + 873 = 29682
Step 35: 29682 + 873 = 30555
Step 36: 30555 + 873 = 31428
Step 37: 31428 + 873 = 32301
Step 38: 32301 + 873 = 33174
Step 39: 33174 + 873 = 34047
Step 40: 34047 + 873 = 34920
Step 41: 34920 + 873 = 35793
Step 42: 35793 + 873 = 36666
Step 43: 36666 + 873 = 37539
Step 44: 37539 + 873 = 38412
Step 45: 38412 + 873 = 39285
Step 46: 39285 + 873 = 40158
Step 47: 40158 + 873 = 41031
Step 48: 41031 + 873 = 41904
Step 49: 41904 + 873 = 42777
Step 50: 42777 + 873 = 43650
Step 51: 43650 + 873 = 44523
Step 52: 44523 + 873 = 45396
Step 53: 45396 + 873 = 46269
Step 54: 46269 + 873 = 47142
Step 55: 47142 + 873 = 48015
Step 56: 48015 + 873 = 48888
Step 57: 48888 + 873 = 49761
Step 58: 49761 + 873 = 50634
Step 59: 50634 + 873 = 51507
Step 60: 51507 + 873 = 52380
Step 61: 52380 + 873 = 53253
Step 62: 53253 + 873 = 54126
Step 63: 54126 + 873 = 54999
Step 64: 54999 + 873 = 55872
Step 65: 55872 + 873 = 56745
Step 66: 56745 + 873 = 57618
Step 67: 57618 + 873 = 58491
Step 68: 58491 + 873 = 59364
Step 69: 59364 + 873 = 60237
Step 70: 60237 + 873 = 61110
Step 71: 61110 + 873 = 61983
Step 72: 61983 + 873 = 62856
Step 73: 62856 + 873 = 63729
Step 74: 63729 + 873 = 64602
Step 75: 64602 + 873 = 65475
Step 76: 65475 + 873 = 66348
Step 77: 66348 + 873 = 67221
Step 78: 67221 + 873 = 68094
Step 79: 68094 + 873 = 68967
Step 80: 68967 + 873 = 69840
Step 81: 69840 + 873 = 70713
Step 82: 70713 + 873 = 71586
Step 83: 71586 + 873 = 72459
Step 84: 72459 + 873 = 73332
Step 85: 73332 + 873 = 74205
Step 86: 74205 + 873 = 75078
Step 87: 75078 + 873 = 75951
Step 88: 75951 + 873 = 76824
Step 89: 76824 + 873 = 77697
Step 90: 77697 + 873 = 78570
Step 91: 78570 + 873 = 79443
Step 92: 79443 + 873 = 80316
Step 93: 80316 + 873 = 81189
Step 94: 81189 + 873 = 82062
Step 95: 82062 + 873 = 82935
Step 96: 82935 + 873 = 83808
Step 97: 83808 + 873 = 84681
Step 98: 84681 + 873 = 85554
Step 99: 85554 + 873 = 86427
Step 100: 86427 + 873 = 87300
Step 101: 87300 + 873 = 88173
Step 102: 88173 + 873 = 89046
Step 103: 89046 + 873 = 89919
Step 104: 89919 + 873 = 90792
Step 105: 90792 + 873 = 91665
Step 106: 91665 + 873 = 92538
Step 107: 92538 + 873 = 93411
Step 108: 93411 + 873 = 94284
Step 109: 94284 + 873 = 95157
Step 110: 95157 + 873 = 96030
Step 111: 96030 + 873 = 96903
Step 112: 96903 + 873 = 97776
Step 113: 97776 + 873 = 98649
Step 114: 98649 + 873 = 99522
Step 115: 99522 + 873 = 100395
Step 116: 100395 + 873 = 101268
Step 117: 101268 + 873 = 102141
Step 118: 102141 + 873 = 103014
Step 119: 103014 + 873 = 103887
Step 120: 103887 + 873 = 104760
Step 121: 104760 + 873 = 105633
Step 122: 105633 + 873 = 106506
Step 123: 106506 + 873 = 107379
Step 124: 107379 + 873 = 108252
Step 125: 108252 + 873 = 109125
Step 126: 109125 + 873 = 109998
Step 127: 109998 + 873 = 110871
Step 128: 110871 + 873 = 111744
Step 129: 111744 + 873 = 112617
Step 130: 112617 + 873 = 113490
Step 131: 113490 + 873 = 114363
Step 132: 114363 + 873 = 115236
Step 133: 115236 + 873 = 116109
Step 134: 116109 + 873 = 116982
Step 135: 116982 + 873 = 117855
Step 136: 117855 + 873 = 118728
Step 137: 118728 + 873 = 119601
Step 138: 119601 + 873 = 120474
Step 139: 120474 + 873 = 121347

So, 873*139 = 121347