OK, let's work through this together. We're starting with 815 and we're going to multiply it by 181, which means we add 815 to itself 181 times.
Step 1: 0 + 815 = 815
Step 2: 815 + 815 = 1630
Step 3: 1630 + 815 = 2445
Step 4: 2445 + 815 = 3260
Step 5: 3260 + 815 = 4075
Step 6: 4075 + 815 = 4890
Step 7: 4890 + 815 = 5705
Step 8: 5705 + 815 = 6520
Step 9: 6520 + 815 = 7335
Step 10: 7335 + 815 = 8150
Step 11: 8150 + 815 = 8965
Step 12: 8965 + 815 = 9780
Step 13: 9780 + 815 = 10595
Step 14: 10595 + 815 = 11410
Step 15: 11410 + 815 = 12225
Step 16: 12225 + 815 = 13040
Step 17: 13040 + 815 = 13855
Step 18: 13855 + 815 = 14670
Step 19: 14670 + 815 = 15485
Step 20: 15485 + 815 = 16300
Step 21: 16300 + 815 = 17115
Step 22: 17115 + 815 = 17930
Step 23: 17930 + 815 = 18745
Step 24: 18745 + 815 = 19560
Step 25: 19560 + 815 = 20375
Step 26: 20375 + 815 = 21190
Step 27: 21190 + 815 = 22005
Step 28: 22005 + 815 = 22820
Step 29: 22820 + 815 = 23635
Step 30: 23635 + 815 = 24450
Step 31: 24450 + 815 = 25265
Step 32: 25265 + 815 = 26080
Step 33: 26080 + 815 = 26895
Step 34: 26895 + 815 = 27710
Step 35: 27710 + 815 = 28525
Step 36: 28525 + 815 = 29340
Step 37: 29340 + 815 = 30155
Step 38: 30155 + 815 = 30970
Step 39: 30970 + 815 = 31785
Step 40: 31785 + 815 = 32600
Step 41: 32600 + 815 = 33415
Step 42: 33415 + 815 = 34230
Step 43: 34230 + 815 = 35045
Step 44: 35045 + 815 = 35860
Step 45: 35860 + 815 = 36675
Step 46: 36675 + 815 = 37490
Step 47: 37490 + 815 = 38305
Step 48: 38305 + 815 = 39120
Step 49: 39120 + 815 = 39935
Step 50: 39935 + 815 = 40750
Step 51: 40750 + 815 = 41565
Step 52: 41565 + 815 = 42380
Step 53: 42380 + 815 = 43195
Step 54: 43195 + 815 = 44010
Step 55: 44010 + 815 = 44825
Step 56: 44825 + 815 = 45640
Step 57: 45640 + 815 = 46455
Step 58: 46455 + 815 = 47270
Step 59: 47270 + 815 = 48085
Step 60: 48085 + 815 = 48900
Step 61: 48900 + 815 = 49715
Step 62: 49715 + 815 = 50530
Step 63: 50530 + 815 = 51345
Step 64: 51345 + 815 = 52160
Step 65: 52160 + 815 = 52975
Step 66: 52975 + 815 = 53790
Step 67: 53790 + 815 = 54605
Step 68: 54605 + 815 = 55420
Step 69: 55420 + 815 = 56235
Step 70: 56235 + 815 = 57050
Step 71: 57050 + 815 = 57865
Step 72: 57865 + 815 = 58680
Step 73: 58680 + 815 = 59495
Step 74: 59495 + 815 = 60310
Step 75: 60310 + 815 = 61125
Step 76: 61125 + 815 = 61940
Step 77: 61940 + 815 = 62755
Step 78: 62755 + 815 = 63570
Step 79: 63570 + 815 = 64385
Step 80: 64385 + 815 = 65200
Step 81: 65200 + 815 = 66015
Step 82: 66015 + 815 = 66830
Step 83: 66830 + 815 = 67645
Step 84: 67645 + 815 = 68460
Step 85: 68460 + 815 = 69275
Step 86: 69275 + 815 = 70090
Step 87: 70090 + 815 = 70905
Step 88: 70905 + 815 = 71720
Step 89: 71720 + 815 = 72535
Step 90: 72535 + 815 = 73350
Step 91: 73350 + 815 = 74165
Step 92: 74165 + 815 = 74980
Step 93: 74980 + 815 = 75795
Step 94: 75795 + 815 = 76610
Step 95: 76610 + 815 = 77425
Step 96: 77425 + 815 = 78240
Step 97: 78240 + 815 = 79055
Step 98: 79055 + 815 = 79870
Step 99: 79870 + 815 = 80685
Step 100: 80685 + 815 = 81500
Step 101: 81500 + 815 = 82315
Step 102: 82315 + 815 = 83130
Step 103: 83130 + 815 = 83945
Step 104: 83945 + 815 = 84760
Step 105: 84760 + 815 = 85575
Step 106: 85575 + 815 = 86390
Step 107: 86390 + 815 = 87205
Step 108: 87205 + 815 = 88020
Step 109: 88020 + 815 = 88835
Step 110: 88835 + 815 = 89650
Step 111: 89650 + 815 = 90465
Step 112: 90465 + 815 = 91280
Step 113: 91280 + 815 = 92095
Step 114: 92095 + 815 = 92910
Step 115: 92910 + 815 = 93725
Step 116: 93725 + 815 = 94540
Step 117: 94540 + 815 = 95355
Step 118: 95355 + 815 = 96170
Step 119: 96170 + 815 = 96985
Step 120: 96985 + 815 = 97800
Step 121: 97800 + 815 = 98615
Step 122: 98615 + 815 = 99430
Step 123: 99430 + 815 = 100245
Step 124: 100245 + 815 = 101060
Step 125: 101060 + 815 = 101875
Step 126: 101875 + 815 = 102690
Step 127: 102690 + 815 = 103505
Step 128: 103505 + 815 = 104320
Step 129: 104320 + 815 = 105135
Step 130: 105135 + 815 = 105950
Step 131: 105950 + 815 = 106765
Step 132: 106765 + 815 = 107580
Step 133: 107580 + 815 = 108395
Step 134: 108395 + 815 = 109210
Step 135: 109210 + 815 = 110025
Step 136: 110025 + 815 = 110840
Step 137: 110840 + 815 = 111655
Step 138: 111655 + 815 = 112470
Step 139: 112470 + 815 = 113285
Step 140: 113285 + 815 = 114100
Step 141: 114100 + 815 = 114915
Step 142: 114915 + 815 = 115730
Step 143: 115730 + 815 = 116545
Step 144: 116545 + 815 = 117360
Step 145: 117360 + 815 = 118175
Step 146: 118175 + 815 = 118990
Step 147: 118990 + 815 = 119805
Step 148: 119805 + 815 = 120620
Step 149: 120620 + 815 = 121435
Step 150: 121435 + 815 = 122250
Step 151: 122250 + 815 = 123065
Step 152: 123065 + 815 = 123880
Step 153: 123880 + 815 = 124695
Step 154: 124695 + 815 = 125510
Step 155: 125510 + 815 = 126325
Step 156: 126325 + 815 = 127140
Step 157: 127140 + 815 = 127955
Step 158: 127955 + 815 = 128770
Step 159: 128770 + 815 = 129585
Step 160: 129585 + 815 = 130400
Step 161: 130400 + 815 = 131215
Step 162: 131215 + 815 = 132030
Step 163: 132030 + 815 = 132845
Step 164: 132845 + 815 = 133660
Step 165: 133660 + 815 = 134475
Step 166: 134475 + 815 = 135290
Step 167: 135290 + 815 = 136105
Step 168: 136105 + 815 = 136920
Step 169: 136920 + 815 = 137735
Step 170: 137735 + 815 = 138550
Step 171: 138550 + 815 = 139365
Step 172: 139365 + 815 = 140180
Step 173: 140180 + 815 = 140995
Step 174: 140995 + 815 = 141810
Step 175: 141810 + 815 = 142625
Step 176: 142625 + 815 = 143440
Step 177: 143440 + 815 = 144255
Step 178: 144255 + 815 = 145070
Step 179: 145070 + 815 = 145885
Step 180: 145885 + 815 = 146700
Step 181: 146700 + 815 = 147515

So, 815*181 = 147515