Alright, let's solve this math problem step by step. First, we have the number 639. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 447. So, we're going to take the number 639 and add it to itself 447 times.
Step 1: 0 + 639 = 639
Step 2: 639 + 639 = 1278
Step 3: 1278 + 639 = 1917
Step 4: 1917 + 639 = 2556
Step 5: 2556 + 639 = 3195
Step 6: 3195 + 639 = 3834
Step 7: 3834 + 639 = 4473
Step 8: 4473 + 639 = 5112
Step 9: 5112 + 639 = 5751
Step 10: 5751 + 639 = 6390
Step 11: 6390 + 639 = 7029
Step 12: 7029 + 639 = 7668
Step 13: 7668 + 639 = 8307
Step 14: 8307 + 639 = 8946
Step 15: 8946 + 639 = 9585
Step 16: 9585 + 639 = 10224
Step 17: 10224 + 639 = 10863
Step 18: 10863 + 639 = 11502
Step 19: 11502 + 639 = 12141
Step 20: 12141 + 639 = 12780
Step 21: 12780 + 639 = 13419
Step 22: 13419 + 639 = 14058
Step 23: 14058 + 639 = 14697
Step 24: 14697 + 639 = 15336
Step 25: 15336 + 639 = 15975
Step 26: 15975 + 639 = 16614
Step 27: 16614 + 639 = 17253
Step 28: 17253 + 639 = 17892
Step 29: 17892 + 639 = 18531
Step 30: 18531 + 639 = 19170
Step 31: 19170 + 639 = 19809
Step 32: 19809 + 639 = 20448
Step 33: 20448 + 639 = 21087
Step 34: 21087 + 639 = 21726
Step 35: 21726 + 639 = 22365
Step 36: 22365 + 639 = 23004
Step 37: 23004 + 639 = 23643
Step 38: 23643 + 639 = 24282
Step 39: 24282 + 639 = 24921
Step 40: 24921 + 639 = 25560
Step 41: 25560 + 639 = 26199
Step 42: 26199 + 639 = 26838
Step 43: 26838 + 639 = 27477
Step 44: 27477 + 639 = 28116
Step 45: 28116 + 639 = 28755
Step 46: 28755 + 639 = 29394
Step 47: 29394 + 639 = 30033
Step 48: 30033 + 639 = 30672
Step 49: 30672 + 639 = 31311
Step 50: 31311 + 639 = 31950
Step 51: 31950 + 639 = 32589
Step 52: 32589 + 639 = 33228
Step 53: 33228 + 639 = 33867
Step 54: 33867 + 639 = 34506
Step 55: 34506 + 639 = 35145
Step 56: 35145 + 639 = 35784
Step 57: 35784 + 639 = 36423
Step 58: 36423 + 639 = 37062
Step 59: 37062 + 639 = 37701
Step 60: 37701 + 639 = 38340
Step 61: 38340 + 639 = 38979
Step 62: 38979 + 639 = 39618
Step 63: 39618 + 639 = 40257
Step 64: 40257 + 639 = 40896
Step 65: 40896 + 639 = 41535
Step 66: 41535 + 639 = 42174
Step 67: 42174 + 639 = 42813
Step 68: 42813 + 639 = 43452
Step 69: 43452 + 639 = 44091
Step 70: 44091 + 639 = 44730
Step 71: 44730 + 639 = 45369
Step 72: 45369 + 639 = 46008
Step 73: 46008 + 639 = 46647
Step 74: 46647 + 639 = 47286
Step 75: 47286 + 639 = 47925
Step 76: 47925 + 639 = 48564
Step 77: 48564 + 639 = 49203
Step 78: 49203 + 639 = 49842
Step 79: 49842 + 639 = 50481
Step 80: 50481 + 639 = 51120
Step 81: 51120 + 639 = 51759
Step 82: 51759 + 639 = 52398
Step 83: 52398 + 639 = 53037
Step 84: 53037 + 639 = 53676
Step 85: 53676 + 639 = 54315
Step 86: 54315 + 639 = 54954
Step 87: 54954 + 639 = 55593
Step 88: 55593 + 639 = 56232
Step 89: 56232 + 639 = 56871
Step 90: 56871 + 639 = 57510
Step 91: 57510 + 639 = 58149
Step 92: 58149 + 639 = 58788
Step 93: 58788 + 639 = 59427
Step 94: 59427 + 639 = 60066
Step 95: 60066 + 639 = 60705
Step 96: 60705 + 639 = 61344
Step 97: 61344 + 639 = 61983
Step 98: 61983 + 639 = 62622
Step 99: 62622 + 639 = 63261
Step 100: 63261 + 639 = 63900
Step 101: 63900 + 639 = 64539
Step 102: 64539 + 639 = 65178
Step 103: 65178 + 639 = 65817
Step 104: 65817 + 639 = 66456
Step 105: 66456 + 639 = 67095
Step 106: 67095 + 639 = 67734
Step 107: 67734 + 639 = 68373
Step 108: 68373 + 639 = 69012
Step 109: 69012 + 639 = 69651
Step 110: 69651 + 639 = 70290
Step 111: 70290 + 639 = 70929
Step 112: 70929 + 639 = 71568
Step 113: 71568 + 639 = 72207
Step 114: 72207 + 639 = 72846
Step 115: 72846 + 639 = 73485
Step 116: 73485 + 639 = 74124
Step 117: 74124 + 639 = 74763
Step 118: 74763 + 639 = 75402
Step 119: 75402 + 639 = 76041
Step 120: 76041 + 639 = 76680
Step 121: 76680 + 639 = 77319
Step 122: 77319 + 639 = 77958
Step 123: 77958 + 639 = 78597
Step 124: 78597 + 639 = 79236
Step 125: 79236 + 639 = 79875
Step 126: 79875 + 639 = 80514
Step 127: 80514 + 639 = 81153
Step 128: 81153 + 639 = 81792
Step 129: 81792 + 639 = 82431
Step 130: 82431 + 639 = 83070
Step 131: 83070 + 639 = 83709
Step 132: 83709 + 639 = 84348
Step 133: 84348 + 639 = 84987
Step 134: 84987 + 639 = 85626
Step 135: 85626 + 639 = 86265
Step 136: 86265 + 639 = 86904
Step 137: 86904 + 639 = 87543
Step 138: 87543 + 639 = 88182
Step 139: 88182 + 639 = 88821
Step 140: 88821 + 639 = 89460
Step 141: 89460 + 639 = 90099
Step 142: 90099 + 639 = 90738
Step 143: 90738 + 639 = 91377
Step 144: 91377 + 639 = 92016
Step 145: 92016 + 639 = 92655
Step 146: 92655 + 639 = 93294
Step 147: 93294 + 639 = 93933
Step 148: 93933 + 639 = 94572
Step 149: 94572 + 639 = 95211
Step 150: 95211 + 639 = 95850
Step 151: 95850 + 639 = 96489
Step 152: 96489 + 639 = 97128
Step 153: 97128 + 639 = 97767
Step 154: 97767 + 639 = 98406
Step 155: 98406 + 639 = 99045
Step 156: 99045 + 639 = 99684
Step 157: 99684 + 639 = 100323
Step 158: 100323 + 639 = 100962
Step 159: 100962 + 639 = 101601
Step 160: 101601 + 639 = 102240
Step 161: 102240 + 639 = 102879
Step 162: 102879 + 639 = 103518
Step 163: 103518 + 639 = 104157
Step 164: 104157 + 639 = 104796
Step 165: 104796 + 639 = 105435
Step 166: 105435 + 639 = 106074
Step 167: 106074 + 639 = 106713
Step 168: 106713 + 639 = 107352
Step 169: 107352 + 639 = 107991
Step 170: 107991 + 639 = 108630
Step 171: 108630 + 639 = 109269
Step 172: 109269 + 639 = 109908
Step 173: 109908 + 639 = 110547
Step 174: 110547 + 639 = 111186
Step 175: 111186 + 639 = 111825
Step 176: 111825 + 639 = 112464
Step 177: 112464 + 639 = 113103
Step 178: 113103 + 639 = 113742
Step 179: 113742 + 639 = 114381
Step 180: 114381 + 639 = 115020
Step 181: 115020 + 639 = 115659
Step 182: 115659 + 639 = 116298
Step 183: 116298 + 639 = 116937
Step 184: 116937 + 639 = 117576
Step 185: 117576 + 639 = 118215
Step 186: 118215 + 639 = 118854
Step 187: 118854 + 639 = 119493
Step 188: 119493 + 639 = 120132
Step 189: 120132 + 639 = 120771
Step 190: 120771 + 639 = 121410
Step 191: 121410 + 639 = 122049
Step 192: 122049 + 639 = 122688
Step 193: 122688 + 639 = 123327
Step 194: 123327 + 639 = 123966
Step 195: 123966 + 639 = 124605
Step 196: 124605 + 639 = 125244
Step 197: 125244 + 639 = 125883
Step 198: 125883 + 639 = 126522
Step 199: 126522 + 639 = 127161
Step 200: 127161 + 639 = 127800
Step 201: 127800 + 639 = 128439
Step 202: 128439 + 639 = 129078
Step 203: 129078 + 639 = 129717
Step 204: 129717 + 639 = 130356
Step 205: 130356 + 639 = 130995
Step 206: 130995 + 639 = 131634
Step 207: 131634 + 639 = 132273
Step 208: 132273 + 639 = 132912
Step 209: 132912 + 639 = 133551
Step 210: 133551 + 639 = 134190
Step 211: 134190 + 639 = 134829
Step 212: 134829 + 639 = 135468
Step 213: 135468 + 639 = 136107
Step 214: 136107 + 639 = 136746
Step 215: 136746 + 639 = 137385
Step 216: 137385 + 639 = 138024
Step 217: 138024 + 639 = 138663
Step 218: 138663 + 639 = 139302
Step 219: 139302 + 639 = 139941
Step 220: 139941 + 639 = 140580
Step 221: 140580 + 639 = 141219
Step 222: 141219 + 639 = 141858
Step 223: 141858 + 639 = 142497
Step 224: 142497 + 639 = 143136
Step 225: 143136 + 639 = 143775
Step 226: 143775 + 639 = 144414
Step 227: 144414 + 639 = 145053
Step 228: 145053 + 639 = 145692
Step 229: 145692 + 639 = 146331
Step 230: 146331 + 639 = 146970
Step 231: 146970 + 639 = 147609
Step 232: 147609 + 639 = 148248
Step 233: 148248 + 639 = 148887
Step 234: 148887 + 639 = 149526
Step 235: 149526 + 639 = 150165
Step 236: 150165 + 639 = 150804
Step 237: 150804 + 639 = 151443
Step 238: 151443 + 639 = 152082
Step 239: 152082 + 639 = 152721
Step 240: 152721 + 639 = 153360
Step 241: 153360 + 639 = 153999
Step 242: 153999 + 639 = 154638
Step 243: 154638 + 639 = 155277
Step 244: 155277 + 639 = 155916
Step 245: 155916 + 639 = 156555
Step 246: 156555 + 639 = 157194
Step 247: 157194 + 639 = 157833
Step 248: 157833 + 639 = 158472
Step 249: 158472 + 639 = 159111
Step 250: 159111 + 639 = 159750
Step 251: 159750 + 639 = 160389
Step 252: 160389 + 639 = 161028
Step 253: 161028 + 639 = 161667
Step 254: 161667 + 639 = 162306
Step 255: 162306 + 639 = 162945
Step 256: 162945 + 639 = 163584
Step 257: 163584 + 639 = 164223
Step 258: 164223 + 639 = 164862
Step 259: 164862 + 639 = 165501
Step 260: 165501 + 639 = 166140
Step 261: 166140 + 639 = 166779
Step 262: 166779 + 639 = 167418
Step 263: 167418 + 639 = 168057
Step 264: 168057 + 639 = 168696
Step 265: 168696 + 639 = 169335
Step 266: 169335 + 639 = 169974
Step 267: 169974 + 639 = 170613
Step 268: 170613 + 639 = 171252
Step 269: 171252 + 639 = 171891
Step 270: 171891 + 639 = 172530
Step 271: 172530 + 639 = 173169
Step 272: 173169 + 639 = 173808
Step 273: 173808 + 639 = 174447
Step 274: 174447 + 639 = 175086
Step 275: 175086 + 639 = 175725
Step 276: 175725 + 639 = 176364
Step 277: 176364 + 639 = 177003
Step 278: 177003 + 639 = 177642
Step 279: 177642 + 639 = 178281
Step 280: 178281 + 639 = 178920
Step 281: 178920 + 639 = 179559
Step 282: 179559 + 639 = 180198
Step 283: 180198 + 639 = 180837
Step 284: 180837 + 639 = 181476
Step 285: 181476 + 639 = 182115
Step 286: 182115 + 639 = 182754
Step 287: 182754 + 639 = 183393
Step 288: 183393 + 639 = 184032
Step 289: 184032 + 639 = 184671
Step 290: 184671 + 639 = 185310
Step 291: 185310 + 639 = 185949
Step 292: 185949 + 639 = 186588
Step 293: 186588 + 639 = 187227
Step 294: 187227 + 639 = 187866
Step 295: 187866 + 639 = 188505
Step 296: 188505 + 639 = 189144
Step 297: 189144 + 639 = 189783
Step 298: 189783 + 639 = 190422
Step 299: 190422 + 639 = 191061
Step 300: 191061 + 639 = 191700
Step 301: 191700 + 639 = 192339
Step 302: 192339 + 639 = 192978
Step 303: 192978 + 639 = 193617
Step 304: 193617 + 639 = 194256
Step 305: 194256 + 639 = 194895
Step 306: 194895 + 639 = 195534
Step 307: 195534 + 639 = 196173
Step 308: 196173 + 639 = 196812
Step 309: 196812 + 639 = 197451
Step 310: 197451 + 639 = 198090
Step 311: 198090 + 639 = 198729
Step 312: 198729 + 639 = 199368
Step 313: 199368 + 639 = 200007
Step 314: 200007 + 639 = 200646
Step 315: 200646 + 639 = 201285
Step 316: 201285 + 639 = 201924
Step 317: 201924 + 639 = 202563
Step 318: 202563 + 639 = 203202
Step 319: 203202 + 639 = 203841
Step 320: 203841 + 639 = 204480
Step 321: 204480 + 639 = 205119
Step 322: 205119 + 639 = 205758
Step 323: 205758 + 639 = 206397
Step 324: 206397 + 639 = 207036
Step 325: 207036 + 639 = 207675
Step 326: 207675 + 639 = 208314
Step 327: 208314 + 639 = 208953
Step 328: 208953 + 639 = 209592
Step 329: 209592 + 639 = 210231
Step 330: 210231 + 639 = 210870
Step 331: 210870 + 639 = 211509
Step 332: 211509 + 639 = 212148
Step 333: 212148 + 639 = 212787
Step 334: 212787 + 639 = 213426
Step 335: 213426 + 639 = 214065
Step 336: 214065 + 639 = 214704
Step 337: 214704 + 639 = 215343
Step 338: 215343 + 639 = 215982
Step 339: 215982 + 639 = 216621
Step 340: 216621 + 639 = 217260
Step 341: 217260 + 639 = 217899
Step 342: 217899 + 639 = 218538
Step 343: 218538 + 639 = 219177
Step 344: 219177 + 639 = 219816
Step 345: 219816 + 639 = 220455
Step 346: 220455 + 639 = 221094
Step 347: 221094 + 639 = 221733
Step 348: 221733 + 639 = 222372
Step 349: 222372 + 639 = 223011
Step 350: 223011 + 639 = 223650
Step 351: 223650 + 639 = 224289
Step 352: 224289 + 639 = 224928
Step 353: 224928 + 639 = 225567
Step 354: 225567 + 639 = 226206
Step 355: 226206 + 639 = 226845
Step 356: 226845 + 639 = 227484
Step 357: 227484 + 639 = 228123
Step 358: 228123 + 639 = 228762
Step 359: 228762 + 639 = 229401
Step 360: 229401 + 639 = 230040
Step 361: 230040 + 639 = 230679
Step 362: 230679 + 639 = 231318
Step 363: 231318 + 639 = 231957
Step 364: 231957 + 639 = 232596
Step 365: 232596 + 639 = 233235
Step 366: 233235 + 639 = 233874
Step 367: 233874 + 639 = 234513
Step 368: 234513 + 639 = 235152
Step 369: 235152 + 639 = 235791
Step 370: 235791 + 639 = 236430
Step 371: 236430 + 639 = 237069
Step 372: 237069 + 639 = 237708
Step 373: 237708 + 639 = 238347
Step 374: 238347 + 639 = 238986
Step 375: 238986 + 639 = 239625
Step 376: 239625 + 639 = 240264
Step 377: 240264 + 639 = 240903
Step 378: 240903 + 639 = 241542
Step 379: 241542 + 639 = 242181
Step 380: 242181 + 639 = 242820
Step 381: 242820 + 639 = 243459
Step 382: 243459 + 639 = 244098
Step 383: 244098 + 639 = 244737
Step 384: 244737 + 639 = 245376
Step 385: 245376 + 639 = 246015
Step 386: 246015 + 639 = 246654
Step 387: 246654 + 639 = 247293
Step 388: 247293 + 639 = 247932
Step 389: 247932 + 639 = 248571
Step 390: 248571 + 639 = 249210
Step 391: 249210 + 639 = 249849
Step 392: 249849 + 639 = 250488
Step 393: 250488 + 639 = 251127
Step 394: 251127 + 639 = 251766
Step 395: 251766 + 639 = 252405
Step 396: 252405 + 639 = 253044
Step 397: 253044 + 639 = 253683
Step 398: 253683 + 639 = 254322
Step 399: 254322 + 639 = 254961
Step 400: 254961 + 639 = 255600
Step 401: 255600 + 639 = 256239
Step 402: 256239 + 639 = 256878
Step 403: 256878 + 639 = 257517
Step 404: 257517 + 639 = 258156
Step 405: 258156 + 639 = 258795
Step 406: 258795 + 639 = 259434
Step 407: 259434 + 639 = 260073
Step 408: 260073 + 639 = 260712
Step 409: 260712 + 639 = 261351
Step 410: 261351 + 639 = 261990
Step 411: 261990 + 639 = 262629
Step 412: 262629 + 639 = 263268
Step 413: 263268 + 639 = 263907
Step 414: 263907 + 639 = 264546
Step 415: 264546 + 639 = 265185
Step 416: 265185 + 639 = 265824
Step 417: 265824 + 639 = 266463
Step 418: 266463 + 639 = 267102
Step 419: 267102 + 639 = 267741
Step 420: 267741 + 639 = 268380
Step 421: 268380 + 639 = 269019
Step 422: 269019 + 639 = 269658
Step 423: 269658 + 639 = 270297
Step 424: 270297 + 639 = 270936
Step 425: 270936 + 639 = 271575
Step 426: 271575 + 639 = 272214
Step 427: 272214 + 639 = 272853
Step 428: 272853 + 639 = 273492
Step 429: 273492 + 639 = 274131
Step 430: 274131 + 639 = 274770
Step 431: 274770 + 639 = 275409
Step 432: 275409 + 639 = 276048
Step 433: 276048 + 639 = 276687
Step 434: 276687 + 639 = 277326
Step 435: 277326 + 639 = 277965
Step 436: 277965 + 639 = 278604
Step 437: 278604 + 639 = 279243
Step 438: 279243 + 639 = 279882
Step 439: 279882 + 639 = 280521
Step 440: 280521 + 639 = 281160
Step 441: 281160 + 639 = 281799
Step 442: 281799 + 639 = 282438
Step 443: 282438 + 639 = 283077
Step 444: 283077 + 639 = 283716
Step 445: 283716 + 639 = 284355
Step 446: 284355 + 639 = 284994
Step 447: 284994 + 639 = 285633

So, 639*447 = 285633