Let's roll up our sleeves and solve this. We have 815 and we're going to multiply it by 404, essentially adding 815 to itself 404 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
Step 182: 147515 + 815 = 148330
Step 183: 148330 + 815 = 149145
Step 184: 149145 + 815 = 149960
Step 185: 149960 + 815 = 150775
Step 186: 150775 + 815 = 151590
Step 187: 151590 + 815 = 152405
Step 188: 152405 + 815 = 153220
Step 189: 153220 + 815 = 154035
Step 190: 154035 + 815 = 154850
Step 191: 154850 + 815 = 155665
Step 192: 155665 + 815 = 156480
Step 193: 156480 + 815 = 157295
Step 194: 157295 + 815 = 158110
Step 195: 158110 + 815 = 158925
Step 196: 158925 + 815 = 159740
Step 197: 159740 + 815 = 160555
Step 198: 160555 + 815 = 161370
Step 199: 161370 + 815 = 162185
Step 200: 162185 + 815 = 163000
Step 201: 163000 + 815 = 163815
Step 202: 163815 + 815 = 164630
Step 203: 164630 + 815 = 165445
Step 204: 165445 + 815 = 166260
Step 205: 166260 + 815 = 167075
Step 206: 167075 + 815 = 167890
Step 207: 167890 + 815 = 168705
Step 208: 168705 + 815 = 169520
Step 209: 169520 + 815 = 170335
Step 210: 170335 + 815 = 171150
Step 211: 171150 + 815 = 171965
Step 212: 171965 + 815 = 172780
Step 213: 172780 + 815 = 173595
Step 214: 173595 + 815 = 174410
Step 215: 174410 + 815 = 175225
Step 216: 175225 + 815 = 176040
Step 217: 176040 + 815 = 176855
Step 218: 176855 + 815 = 177670
Step 219: 177670 + 815 = 178485
Step 220: 178485 + 815 = 179300
Step 221: 179300 + 815 = 180115
Step 222: 180115 + 815 = 180930
Step 223: 180930 + 815 = 181745
Step 224: 181745 + 815 = 182560
Step 225: 182560 + 815 = 183375
Step 226: 183375 + 815 = 184190
Step 227: 184190 + 815 = 185005
Step 228: 185005 + 815 = 185820
Step 229: 185820 + 815 = 186635
Step 230: 186635 + 815 = 187450
Step 231: 187450 + 815 = 188265
Step 232: 188265 + 815 = 189080
Step 233: 189080 + 815 = 189895
Step 234: 189895 + 815 = 190710
Step 235: 190710 + 815 = 191525
Step 236: 191525 + 815 = 192340
Step 237: 192340 + 815 = 193155
Step 238: 193155 + 815 = 193970
Step 239: 193970 + 815 = 194785
Step 240: 194785 + 815 = 195600
Step 241: 195600 + 815 = 196415
Step 242: 196415 + 815 = 197230
Step 243: 197230 + 815 = 198045
Step 244: 198045 + 815 = 198860
Step 245: 198860 + 815 = 199675
Step 246: 199675 + 815 = 200490
Step 247: 200490 + 815 = 201305
Step 248: 201305 + 815 = 202120
Step 249: 202120 + 815 = 202935
Step 250: 202935 + 815 = 203750
Step 251: 203750 + 815 = 204565
Step 252: 204565 + 815 = 205380
Step 253: 205380 + 815 = 206195
Step 254: 206195 + 815 = 207010
Step 255: 207010 + 815 = 207825
Step 256: 207825 + 815 = 208640
Step 257: 208640 + 815 = 209455
Step 258: 209455 + 815 = 210270
Step 259: 210270 + 815 = 211085
Step 260: 211085 + 815 = 211900
Step 261: 211900 + 815 = 212715
Step 262: 212715 + 815 = 213530
Step 263: 213530 + 815 = 214345
Step 264: 214345 + 815 = 215160
Step 265: 215160 + 815 = 215975
Step 266: 215975 + 815 = 216790
Step 267: 216790 + 815 = 217605
Step 268: 217605 + 815 = 218420
Step 269: 218420 + 815 = 219235
Step 270: 219235 + 815 = 220050
Step 271: 220050 + 815 = 220865
Step 272: 220865 + 815 = 221680
Step 273: 221680 + 815 = 222495
Step 274: 222495 + 815 = 223310
Step 275: 223310 + 815 = 224125
Step 276: 224125 + 815 = 224940
Step 277: 224940 + 815 = 225755
Step 278: 225755 + 815 = 226570
Step 279: 226570 + 815 = 227385
Step 280: 227385 + 815 = 228200
Step 281: 228200 + 815 = 229015
Step 282: 229015 + 815 = 229830
Step 283: 229830 + 815 = 230645
Step 284: 230645 + 815 = 231460
Step 285: 231460 + 815 = 232275
Step 286: 232275 + 815 = 233090
Step 287: 233090 + 815 = 233905
Step 288: 233905 + 815 = 234720
Step 289: 234720 + 815 = 235535
Step 290: 235535 + 815 = 236350
Step 291: 236350 + 815 = 237165
Step 292: 237165 + 815 = 237980
Step 293: 237980 + 815 = 238795
Step 294: 238795 + 815 = 239610
Step 295: 239610 + 815 = 240425
Step 296: 240425 + 815 = 241240
Step 297: 241240 + 815 = 242055
Step 298: 242055 + 815 = 242870
Step 299: 242870 + 815 = 243685
Step 300: 243685 + 815 = 244500
Step 301: 244500 + 815 = 245315
Step 302: 245315 + 815 = 246130
Step 303: 246130 + 815 = 246945
Step 304: 246945 + 815 = 247760
Step 305: 247760 + 815 = 248575
Step 306: 248575 + 815 = 249390
Step 307: 249390 + 815 = 250205
Step 308: 250205 + 815 = 251020
Step 309: 251020 + 815 = 251835
Step 310: 251835 + 815 = 252650
Step 311: 252650 + 815 = 253465
Step 312: 253465 + 815 = 254280
Step 313: 254280 + 815 = 255095
Step 314: 255095 + 815 = 255910
Step 315: 255910 + 815 = 256725
Step 316: 256725 + 815 = 257540
Step 317: 257540 + 815 = 258355
Step 318: 258355 + 815 = 259170
Step 319: 259170 + 815 = 259985
Step 320: 259985 + 815 = 260800
Step 321: 260800 + 815 = 261615
Step 322: 261615 + 815 = 262430
Step 323: 262430 + 815 = 263245
Step 324: 263245 + 815 = 264060
Step 325: 264060 + 815 = 264875
Step 326: 264875 + 815 = 265690
Step 327: 265690 + 815 = 266505
Step 328: 266505 + 815 = 267320
Step 329: 267320 + 815 = 268135
Step 330: 268135 + 815 = 268950
Step 331: 268950 + 815 = 269765
Step 332: 269765 + 815 = 270580
Step 333: 270580 + 815 = 271395
Step 334: 271395 + 815 = 272210
Step 335: 272210 + 815 = 273025
Step 336: 273025 + 815 = 273840
Step 337: 273840 + 815 = 274655
Step 338: 274655 + 815 = 275470
Step 339: 275470 + 815 = 276285
Step 340: 276285 + 815 = 277100
Step 341: 277100 + 815 = 277915
Step 342: 277915 + 815 = 278730
Step 343: 278730 + 815 = 279545
Step 344: 279545 + 815 = 280360
Step 345: 280360 + 815 = 281175
Step 346: 281175 + 815 = 281990
Step 347: 281990 + 815 = 282805
Step 348: 282805 + 815 = 283620
Step 349: 283620 + 815 = 284435
Step 350: 284435 + 815 = 285250
Step 351: 285250 + 815 = 286065
Step 352: 286065 + 815 = 286880
Step 353: 286880 + 815 = 287695
Step 354: 287695 + 815 = 288510
Step 355: 288510 + 815 = 289325
Step 356: 289325 + 815 = 290140
Step 357: 290140 + 815 = 290955
Step 358: 290955 + 815 = 291770
Step 359: 291770 + 815 = 292585
Step 360: 292585 + 815 = 293400
Step 361: 293400 + 815 = 294215
Step 362: 294215 + 815 = 295030
Step 363: 295030 + 815 = 295845
Step 364: 295845 + 815 = 296660
Step 365: 296660 + 815 = 297475
Step 366: 297475 + 815 = 298290
Step 367: 298290 + 815 = 299105
Step 368: 299105 + 815 = 299920
Step 369: 299920 + 815 = 300735
Step 370: 300735 + 815 = 301550
Step 371: 301550 + 815 = 302365
Step 372: 302365 + 815 = 303180
Step 373: 303180 + 815 = 303995
Step 374: 303995 + 815 = 304810
Step 375: 304810 + 815 = 305625
Step 376: 305625 + 815 = 306440
Step 377: 306440 + 815 = 307255
Step 378: 307255 + 815 = 308070
Step 379: 308070 + 815 = 308885
Step 380: 308885 + 815 = 309700
Step 381: 309700 + 815 = 310515
Step 382: 310515 + 815 = 311330
Step 383: 311330 + 815 = 312145
Step 384: 312145 + 815 = 312960
Step 385: 312960 + 815 = 313775
Step 386: 313775 + 815 = 314590
Step 387: 314590 + 815 = 315405
Step 388: 315405 + 815 = 316220
Step 389: 316220 + 815 = 317035
Step 390: 317035 + 815 = 317850
Step 391: 317850 + 815 = 318665
Step 392: 318665 + 815 = 319480
Step 393: 319480 + 815 = 320295
Step 394: 320295 + 815 = 321110
Step 395: 321110 + 815 = 321925
Step 396: 321925 + 815 = 322740
Step 397: 322740 + 815 = 323555
Step 398: 323555 + 815 = 324370
Step 399: 324370 + 815 = 325185
Step 400: 325185 + 815 = 326000
Step 401: 326000 + 815 = 326815
Step 402: 326815 + 815 = 327630
Step 403: 327630 + 815 = 328445
Step 404: 328445 + 815 = 329260

So, 815*404 = 329260