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 400. So, we're going to take the number 873 and add it to itself 400 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
Step 187: 162378 + 873 = 163251
Step 188: 163251 + 873 = 164124
Step 189: 164124 + 873 = 164997
Step 190: 164997 + 873 = 165870
Step 191: 165870 + 873 = 166743
Step 192: 166743 + 873 = 167616
Step 193: 167616 + 873 = 168489
Step 194: 168489 + 873 = 169362
Step 195: 169362 + 873 = 170235
Step 196: 170235 + 873 = 171108
Step 197: 171108 + 873 = 171981
Step 198: 171981 + 873 = 172854
Step 199: 172854 + 873 = 173727
Step 200: 173727 + 873 = 174600
Step 201: 174600 + 873 = 175473
Step 202: 175473 + 873 = 176346
Step 203: 176346 + 873 = 177219
Step 204: 177219 + 873 = 178092
Step 205: 178092 + 873 = 178965
Step 206: 178965 + 873 = 179838
Step 207: 179838 + 873 = 180711
Step 208: 180711 + 873 = 181584
Step 209: 181584 + 873 = 182457
Step 210: 182457 + 873 = 183330
Step 211: 183330 + 873 = 184203
Step 212: 184203 + 873 = 185076
Step 213: 185076 + 873 = 185949
Step 214: 185949 + 873 = 186822
Step 215: 186822 + 873 = 187695
Step 216: 187695 + 873 = 188568
Step 217: 188568 + 873 = 189441
Step 218: 189441 + 873 = 190314
Step 219: 190314 + 873 = 191187
Step 220: 191187 + 873 = 192060
Step 221: 192060 + 873 = 192933
Step 222: 192933 + 873 = 193806
Step 223: 193806 + 873 = 194679
Step 224: 194679 + 873 = 195552
Step 225: 195552 + 873 = 196425
Step 226: 196425 + 873 = 197298
Step 227: 197298 + 873 = 198171
Step 228: 198171 + 873 = 199044
Step 229: 199044 + 873 = 199917
Step 230: 199917 + 873 = 200790
Step 231: 200790 + 873 = 201663
Step 232: 201663 + 873 = 202536
Step 233: 202536 + 873 = 203409
Step 234: 203409 + 873 = 204282
Step 235: 204282 + 873 = 205155
Step 236: 205155 + 873 = 206028
Step 237: 206028 + 873 = 206901
Step 238: 206901 + 873 = 207774
Step 239: 207774 + 873 = 208647
Step 240: 208647 + 873 = 209520
Step 241: 209520 + 873 = 210393
Step 242: 210393 + 873 = 211266
Step 243: 211266 + 873 = 212139
Step 244: 212139 + 873 = 213012
Step 245: 213012 + 873 = 213885
Step 246: 213885 + 873 = 214758
Step 247: 214758 + 873 = 215631
Step 248: 215631 + 873 = 216504
Step 249: 216504 + 873 = 217377
Step 250: 217377 + 873 = 218250
Step 251: 218250 + 873 = 219123
Step 252: 219123 + 873 = 219996
Step 253: 219996 + 873 = 220869
Step 254: 220869 + 873 = 221742
Step 255: 221742 + 873 = 222615
Step 256: 222615 + 873 = 223488
Step 257: 223488 + 873 = 224361
Step 258: 224361 + 873 = 225234
Step 259: 225234 + 873 = 226107
Step 260: 226107 + 873 = 226980
Step 261: 226980 + 873 = 227853
Step 262: 227853 + 873 = 228726
Step 263: 228726 + 873 = 229599
Step 264: 229599 + 873 = 230472
Step 265: 230472 + 873 = 231345
Step 266: 231345 + 873 = 232218
Step 267: 232218 + 873 = 233091
Step 268: 233091 + 873 = 233964
Step 269: 233964 + 873 = 234837
Step 270: 234837 + 873 = 235710
Step 271: 235710 + 873 = 236583
Step 272: 236583 + 873 = 237456
Step 273: 237456 + 873 = 238329
Step 274: 238329 + 873 = 239202
Step 275: 239202 + 873 = 240075
Step 276: 240075 + 873 = 240948
Step 277: 240948 + 873 = 241821
Step 278: 241821 + 873 = 242694
Step 279: 242694 + 873 = 243567
Step 280: 243567 + 873 = 244440
Step 281: 244440 + 873 = 245313
Step 282: 245313 + 873 = 246186
Step 283: 246186 + 873 = 247059
Step 284: 247059 + 873 = 247932
Step 285: 247932 + 873 = 248805
Step 286: 248805 + 873 = 249678
Step 287: 249678 + 873 = 250551
Step 288: 250551 + 873 = 251424
Step 289: 251424 + 873 = 252297
Step 290: 252297 + 873 = 253170
Step 291: 253170 + 873 = 254043
Step 292: 254043 + 873 = 254916
Step 293: 254916 + 873 = 255789
Step 294: 255789 + 873 = 256662
Step 295: 256662 + 873 = 257535
Step 296: 257535 + 873 = 258408
Step 297: 258408 + 873 = 259281
Step 298: 259281 + 873 = 260154
Step 299: 260154 + 873 = 261027
Step 300: 261027 + 873 = 261900
Step 301: 261900 + 873 = 262773
Step 302: 262773 + 873 = 263646
Step 303: 263646 + 873 = 264519
Step 304: 264519 + 873 = 265392
Step 305: 265392 + 873 = 266265
Step 306: 266265 + 873 = 267138
Step 307: 267138 + 873 = 268011
Step 308: 268011 + 873 = 268884
Step 309: 268884 + 873 = 269757
Step 310: 269757 + 873 = 270630
Step 311: 270630 + 873 = 271503
Step 312: 271503 + 873 = 272376
Step 313: 272376 + 873 = 273249
Step 314: 273249 + 873 = 274122
Step 315: 274122 + 873 = 274995
Step 316: 274995 + 873 = 275868
Step 317: 275868 + 873 = 276741
Step 318: 276741 + 873 = 277614
Step 319: 277614 + 873 = 278487
Step 320: 278487 + 873 = 279360
Step 321: 279360 + 873 = 280233
Step 322: 280233 + 873 = 281106
Step 323: 281106 + 873 = 281979
Step 324: 281979 + 873 = 282852
Step 325: 282852 + 873 = 283725
Step 326: 283725 + 873 = 284598
Step 327: 284598 + 873 = 285471
Step 328: 285471 + 873 = 286344
Step 329: 286344 + 873 = 287217
Step 330: 287217 + 873 = 288090
Step 331: 288090 + 873 = 288963
Step 332: 288963 + 873 = 289836
Step 333: 289836 + 873 = 290709
Step 334: 290709 + 873 = 291582
Step 335: 291582 + 873 = 292455
Step 336: 292455 + 873 = 293328
Step 337: 293328 + 873 = 294201
Step 338: 294201 + 873 = 295074
Step 339: 295074 + 873 = 295947
Step 340: 295947 + 873 = 296820
Step 341: 296820 + 873 = 297693
Step 342: 297693 + 873 = 298566
Step 343: 298566 + 873 = 299439
Step 344: 299439 + 873 = 300312
Step 345: 300312 + 873 = 301185
Step 346: 301185 + 873 = 302058
Step 347: 302058 + 873 = 302931
Step 348: 302931 + 873 = 303804
Step 349: 303804 + 873 = 304677
Step 350: 304677 + 873 = 305550
Step 351: 305550 + 873 = 306423
Step 352: 306423 + 873 = 307296
Step 353: 307296 + 873 = 308169
Step 354: 308169 + 873 = 309042
Step 355: 309042 + 873 = 309915
Step 356: 309915 + 873 = 310788
Step 357: 310788 + 873 = 311661
Step 358: 311661 + 873 = 312534
Step 359: 312534 + 873 = 313407
Step 360: 313407 + 873 = 314280
Step 361: 314280 + 873 = 315153
Step 362: 315153 + 873 = 316026
Step 363: 316026 + 873 = 316899
Step 364: 316899 + 873 = 317772
Step 365: 317772 + 873 = 318645
Step 366: 318645 + 873 = 319518
Step 367: 319518 + 873 = 320391
Step 368: 320391 + 873 = 321264
Step 369: 321264 + 873 = 322137
Step 370: 322137 + 873 = 323010
Step 371: 323010 + 873 = 323883
Step 372: 323883 + 873 = 324756
Step 373: 324756 + 873 = 325629
Step 374: 325629 + 873 = 326502
Step 375: 326502 + 873 = 327375
Step 376: 327375 + 873 = 328248
Step 377: 328248 + 873 = 329121
Step 378: 329121 + 873 = 329994
Step 379: 329994 + 873 = 330867
Step 380: 330867 + 873 = 331740
Step 381: 331740 + 873 = 332613
Step 382: 332613 + 873 = 333486
Step 383: 333486 + 873 = 334359
Step 384: 334359 + 873 = 335232
Step 385: 335232 + 873 = 336105
Step 386: 336105 + 873 = 336978
Step 387: 336978 + 873 = 337851
Step 388: 337851 + 873 = 338724
Step 389: 338724 + 873 = 339597
Step 390: 339597 + 873 = 340470
Step 391: 340470 + 873 = 341343
Step 392: 341343 + 873 = 342216
Step 393: 342216 + 873 = 343089
Step 394: 343089 + 873 = 343962
Step 395: 343962 + 873 = 344835
Step 396: 344835 + 873 = 345708
Step 397: 345708 + 873 = 346581
Step 398: 346581 + 873 = 347454
Step 399: 347454 + 873 = 348327
Step 400: 348327 + 873 = 349200

So, 873*400 = 349200