OK, let's crack this. We're given 873 and our task is to multiply it by 186. Essentially, we'll be adding 873 to itself 186 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
Step 140: 121347 + 873 = 122220
Step 141: 122220 + 873 = 123093
Step 142: 123093 + 873 = 123966
Step 143: 123966 + 873 = 124839
Step 144: 124839 + 873 = 125712
Step 145: 125712 + 873 = 126585
Step 146: 126585 + 873 = 127458
Step 147: 127458 + 873 = 128331
Step 148: 128331 + 873 = 129204
Step 149: 129204 + 873 = 130077
Step 150: 130077 + 873 = 130950
Step 151: 130950 + 873 = 131823
Step 152: 131823 + 873 = 132696
Step 153: 132696 + 873 = 133569
Step 154: 133569 + 873 = 134442
Step 155: 134442 + 873 = 135315
Step 156: 135315 + 873 = 136188
Step 157: 136188 + 873 = 137061
Step 158: 137061 + 873 = 137934
Step 159: 137934 + 873 = 138807
Step 160: 138807 + 873 = 139680
Step 161: 139680 + 873 = 140553
Step 162: 140553 + 873 = 141426
Step 163: 141426 + 873 = 142299
Step 164: 142299 + 873 = 143172
Step 165: 143172 + 873 = 144045
Step 166: 144045 + 873 = 144918
Step 167: 144918 + 873 = 145791
Step 168: 145791 + 873 = 146664
Step 169: 146664 + 873 = 147537
Step 170: 147537 + 873 = 148410
Step 171: 148410 + 873 = 149283
Step 172: 149283 + 873 = 150156
Step 173: 150156 + 873 = 151029
Step 174: 151029 + 873 = 151902
Step 175: 151902 + 873 = 152775
Step 176: 152775 + 873 = 153648
Step 177: 153648 + 873 = 154521
Step 178: 154521 + 873 = 155394
Step 179: 155394 + 873 = 156267
Step 180: 156267 + 873 = 157140
Step 181: 157140 + 873 = 158013
Step 182: 158013 + 873 = 158886
Step 183: 158886 + 873 = 159759
Step 184: 159759 + 873 = 160632
Step 185: 160632 + 873 = 161505
Step 186: 161505 + 873 = 162378

So, 873*186 = 162378