Alright, let's solve this math problem step by step. First, we have the number 645. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 498. So, we're going to take the number 645 and add it to itself 498 times.
Step 1: 0 + 645 = 645
Step 2: 645 + 645 = 1290
Step 3: 1290 + 645 = 1935
Step 4: 1935 + 645 = 2580
Step 5: 2580 + 645 = 3225
Step 6: 3225 + 645 = 3870
Step 7: 3870 + 645 = 4515
Step 8: 4515 + 645 = 5160
Step 9: 5160 + 645 = 5805
Step 10: 5805 + 645 = 6450
Step 11: 6450 + 645 = 7095
Step 12: 7095 + 645 = 7740
Step 13: 7740 + 645 = 8385
Step 14: 8385 + 645 = 9030
Step 15: 9030 + 645 = 9675
Step 16: 9675 + 645 = 10320
Step 17: 10320 + 645 = 10965
Step 18: 10965 + 645 = 11610
Step 19: 11610 + 645 = 12255
Step 20: 12255 + 645 = 12900
Step 21: 12900 + 645 = 13545
Step 22: 13545 + 645 = 14190
Step 23: 14190 + 645 = 14835
Step 24: 14835 + 645 = 15480
Step 25: 15480 + 645 = 16125
Step 26: 16125 + 645 = 16770
Step 27: 16770 + 645 = 17415
Step 28: 17415 + 645 = 18060
Step 29: 18060 + 645 = 18705
Step 30: 18705 + 645 = 19350
Step 31: 19350 + 645 = 19995
Step 32: 19995 + 645 = 20640
Step 33: 20640 + 645 = 21285
Step 34: 21285 + 645 = 21930
Step 35: 21930 + 645 = 22575
Step 36: 22575 + 645 = 23220
Step 37: 23220 + 645 = 23865
Step 38: 23865 + 645 = 24510
Step 39: 24510 + 645 = 25155
Step 40: 25155 + 645 = 25800
Step 41: 25800 + 645 = 26445
Step 42: 26445 + 645 = 27090
Step 43: 27090 + 645 = 27735
Step 44: 27735 + 645 = 28380
Step 45: 28380 + 645 = 29025
Step 46: 29025 + 645 = 29670
Step 47: 29670 + 645 = 30315
Step 48: 30315 + 645 = 30960
Step 49: 30960 + 645 = 31605
Step 50: 31605 + 645 = 32250
Step 51: 32250 + 645 = 32895
Step 52: 32895 + 645 = 33540
Step 53: 33540 + 645 = 34185
Step 54: 34185 + 645 = 34830
Step 55: 34830 + 645 = 35475
Step 56: 35475 + 645 = 36120
Step 57: 36120 + 645 = 36765
Step 58: 36765 + 645 = 37410
Step 59: 37410 + 645 = 38055
Step 60: 38055 + 645 = 38700
Step 61: 38700 + 645 = 39345
Step 62: 39345 + 645 = 39990
Step 63: 39990 + 645 = 40635
Step 64: 40635 + 645 = 41280
Step 65: 41280 + 645 = 41925
Step 66: 41925 + 645 = 42570
Step 67: 42570 + 645 = 43215
Step 68: 43215 + 645 = 43860
Step 69: 43860 + 645 = 44505
Step 70: 44505 + 645 = 45150
Step 71: 45150 + 645 = 45795
Step 72: 45795 + 645 = 46440
Step 73: 46440 + 645 = 47085
Step 74: 47085 + 645 = 47730
Step 75: 47730 + 645 = 48375
Step 76: 48375 + 645 = 49020
Step 77: 49020 + 645 = 49665
Step 78: 49665 + 645 = 50310
Step 79: 50310 + 645 = 50955
Step 80: 50955 + 645 = 51600
Step 81: 51600 + 645 = 52245
Step 82: 52245 + 645 = 52890
Step 83: 52890 + 645 = 53535
Step 84: 53535 + 645 = 54180
Step 85: 54180 + 645 = 54825
Step 86: 54825 + 645 = 55470
Step 87: 55470 + 645 = 56115
Step 88: 56115 + 645 = 56760
Step 89: 56760 + 645 = 57405
Step 90: 57405 + 645 = 58050
Step 91: 58050 + 645 = 58695
Step 92: 58695 + 645 = 59340
Step 93: 59340 + 645 = 59985
Step 94: 59985 + 645 = 60630
Step 95: 60630 + 645 = 61275
Step 96: 61275 + 645 = 61920
Step 97: 61920 + 645 = 62565
Step 98: 62565 + 645 = 63210
Step 99: 63210 + 645 = 63855
Step 100: 63855 + 645 = 64500
Step 101: 64500 + 645 = 65145
Step 102: 65145 + 645 = 65790
Step 103: 65790 + 645 = 66435
Step 104: 66435 + 645 = 67080
Step 105: 67080 + 645 = 67725
Step 106: 67725 + 645 = 68370
Step 107: 68370 + 645 = 69015
Step 108: 69015 + 645 = 69660
Step 109: 69660 + 645 = 70305
Step 110: 70305 + 645 = 70950
Step 111: 70950 + 645 = 71595
Step 112: 71595 + 645 = 72240
Step 113: 72240 + 645 = 72885
Step 114: 72885 + 645 = 73530
Step 115: 73530 + 645 = 74175
Step 116: 74175 + 645 = 74820
Step 117: 74820 + 645 = 75465
Step 118: 75465 + 645 = 76110
Step 119: 76110 + 645 = 76755
Step 120: 76755 + 645 = 77400
Step 121: 77400 + 645 = 78045
Step 122: 78045 + 645 = 78690
Step 123: 78690 + 645 = 79335
Step 124: 79335 + 645 = 79980
Step 125: 79980 + 645 = 80625
Step 126: 80625 + 645 = 81270
Step 127: 81270 + 645 = 81915
Step 128: 81915 + 645 = 82560
Step 129: 82560 + 645 = 83205
Step 130: 83205 + 645 = 83850
Step 131: 83850 + 645 = 84495
Step 132: 84495 + 645 = 85140
Step 133: 85140 + 645 = 85785
Step 134: 85785 + 645 = 86430
Step 135: 86430 + 645 = 87075
Step 136: 87075 + 645 = 87720
Step 137: 87720 + 645 = 88365
Step 138: 88365 + 645 = 89010
Step 139: 89010 + 645 = 89655
Step 140: 89655 + 645 = 90300
Step 141: 90300 + 645 = 90945
Step 142: 90945 + 645 = 91590
Step 143: 91590 + 645 = 92235
Step 144: 92235 + 645 = 92880
Step 145: 92880 + 645 = 93525
Step 146: 93525 + 645 = 94170
Step 147: 94170 + 645 = 94815
Step 148: 94815 + 645 = 95460
Step 149: 95460 + 645 = 96105
Step 150: 96105 + 645 = 96750
Step 151: 96750 + 645 = 97395
Step 152: 97395 + 645 = 98040
Step 153: 98040 + 645 = 98685
Step 154: 98685 + 645 = 99330
Step 155: 99330 + 645 = 99975
Step 156: 99975 + 645 = 100620
Step 157: 100620 + 645 = 101265
Step 158: 101265 + 645 = 101910
Step 159: 101910 + 645 = 102555
Step 160: 102555 + 645 = 103200
Step 161: 103200 + 645 = 103845
Step 162: 103845 + 645 = 104490
Step 163: 104490 + 645 = 105135
Step 164: 105135 + 645 = 105780
Step 165: 105780 + 645 = 106425
Step 166: 106425 + 645 = 107070
Step 167: 107070 + 645 = 107715
Step 168: 107715 + 645 = 108360
Step 169: 108360 + 645 = 109005
Step 170: 109005 + 645 = 109650
Step 171: 109650 + 645 = 110295
Step 172: 110295 + 645 = 110940
Step 173: 110940 + 645 = 111585
Step 174: 111585 + 645 = 112230
Step 175: 112230 + 645 = 112875
Step 176: 112875 + 645 = 113520
Step 177: 113520 + 645 = 114165
Step 178: 114165 + 645 = 114810
Step 179: 114810 + 645 = 115455
Step 180: 115455 + 645 = 116100
Step 181: 116100 + 645 = 116745
Step 182: 116745 + 645 = 117390
Step 183: 117390 + 645 = 118035
Step 184: 118035 + 645 = 118680
Step 185: 118680 + 645 = 119325
Step 186: 119325 + 645 = 119970
Step 187: 119970 + 645 = 120615
Step 188: 120615 + 645 = 121260
Step 189: 121260 + 645 = 121905
Step 190: 121905 + 645 = 122550
Step 191: 122550 + 645 = 123195
Step 192: 123195 + 645 = 123840
Step 193: 123840 + 645 = 124485
Step 194: 124485 + 645 = 125130
Step 195: 125130 + 645 = 125775
Step 196: 125775 + 645 = 126420
Step 197: 126420 + 645 = 127065
Step 198: 127065 + 645 = 127710
Step 199: 127710 + 645 = 128355
Step 200: 128355 + 645 = 129000
Step 201: 129000 + 645 = 129645
Step 202: 129645 + 645 = 130290
Step 203: 130290 + 645 = 130935
Step 204: 130935 + 645 = 131580
Step 205: 131580 + 645 = 132225
Step 206: 132225 + 645 = 132870
Step 207: 132870 + 645 = 133515
Step 208: 133515 + 645 = 134160
Step 209: 134160 + 645 = 134805
Step 210: 134805 + 645 = 135450
Step 211: 135450 + 645 = 136095
Step 212: 136095 + 645 = 136740
Step 213: 136740 + 645 = 137385
Step 214: 137385 + 645 = 138030
Step 215: 138030 + 645 = 138675
Step 216: 138675 + 645 = 139320
Step 217: 139320 + 645 = 139965
Step 218: 139965 + 645 = 140610
Step 219: 140610 + 645 = 141255
Step 220: 141255 + 645 = 141900
Step 221: 141900 + 645 = 142545
Step 222: 142545 + 645 = 143190
Step 223: 143190 + 645 = 143835
Step 224: 143835 + 645 = 144480
Step 225: 144480 + 645 = 145125
Step 226: 145125 + 645 = 145770
Step 227: 145770 + 645 = 146415
Step 228: 146415 + 645 = 147060
Step 229: 147060 + 645 = 147705
Step 230: 147705 + 645 = 148350
Step 231: 148350 + 645 = 148995
Step 232: 148995 + 645 = 149640
Step 233: 149640 + 645 = 150285
Step 234: 150285 + 645 = 150930
Step 235: 150930 + 645 = 151575
Step 236: 151575 + 645 = 152220
Step 237: 152220 + 645 = 152865
Step 238: 152865 + 645 = 153510
Step 239: 153510 + 645 = 154155
Step 240: 154155 + 645 = 154800
Step 241: 154800 + 645 = 155445
Step 242: 155445 + 645 = 156090
Step 243: 156090 + 645 = 156735
Step 244: 156735 + 645 = 157380
Step 245: 157380 + 645 = 158025
Step 246: 158025 + 645 = 158670
Step 247: 158670 + 645 = 159315
Step 248: 159315 + 645 = 159960
Step 249: 159960 + 645 = 160605
Step 250: 160605 + 645 = 161250
Step 251: 161250 + 645 = 161895
Step 252: 161895 + 645 = 162540
Step 253: 162540 + 645 = 163185
Step 254: 163185 + 645 = 163830
Step 255: 163830 + 645 = 164475
Step 256: 164475 + 645 = 165120
Step 257: 165120 + 645 = 165765
Step 258: 165765 + 645 = 166410
Step 259: 166410 + 645 = 167055
Step 260: 167055 + 645 = 167700
Step 261: 167700 + 645 = 168345
Step 262: 168345 + 645 = 168990
Step 263: 168990 + 645 = 169635
Step 264: 169635 + 645 = 170280
Step 265: 170280 + 645 = 170925
Step 266: 170925 + 645 = 171570
Step 267: 171570 + 645 = 172215
Step 268: 172215 + 645 = 172860
Step 269: 172860 + 645 = 173505
Step 270: 173505 + 645 = 174150
Step 271: 174150 + 645 = 174795
Step 272: 174795 + 645 = 175440
Step 273: 175440 + 645 = 176085
Step 274: 176085 + 645 = 176730
Step 275: 176730 + 645 = 177375
Step 276: 177375 + 645 = 178020
Step 277: 178020 + 645 = 178665
Step 278: 178665 + 645 = 179310
Step 279: 179310 + 645 = 179955
Step 280: 179955 + 645 = 180600
Step 281: 180600 + 645 = 181245
Step 282: 181245 + 645 = 181890
Step 283: 181890 + 645 = 182535
Step 284: 182535 + 645 = 183180
Step 285: 183180 + 645 = 183825
Step 286: 183825 + 645 = 184470
Step 287: 184470 + 645 = 185115
Step 288: 185115 + 645 = 185760
Step 289: 185760 + 645 = 186405
Step 290: 186405 + 645 = 187050
Step 291: 187050 + 645 = 187695
Step 292: 187695 + 645 = 188340
Step 293: 188340 + 645 = 188985
Step 294: 188985 + 645 = 189630
Step 295: 189630 + 645 = 190275
Step 296: 190275 + 645 = 190920
Step 297: 190920 + 645 = 191565
Step 298: 191565 + 645 = 192210
Step 299: 192210 + 645 = 192855
Step 300: 192855 + 645 = 193500
Step 301: 193500 + 645 = 194145
Step 302: 194145 + 645 = 194790
Step 303: 194790 + 645 = 195435
Step 304: 195435 + 645 = 196080
Step 305: 196080 + 645 = 196725
Step 306: 196725 + 645 = 197370
Step 307: 197370 + 645 = 198015
Step 308: 198015 + 645 = 198660
Step 309: 198660 + 645 = 199305
Step 310: 199305 + 645 = 199950
Step 311: 199950 + 645 = 200595
Step 312: 200595 + 645 = 201240
Step 313: 201240 + 645 = 201885
Step 314: 201885 + 645 = 202530
Step 315: 202530 + 645 = 203175
Step 316: 203175 + 645 = 203820
Step 317: 203820 + 645 = 204465
Step 318: 204465 + 645 = 205110
Step 319: 205110 + 645 = 205755
Step 320: 205755 + 645 = 206400
Step 321: 206400 + 645 = 207045
Step 322: 207045 + 645 = 207690
Step 323: 207690 + 645 = 208335
Step 324: 208335 + 645 = 208980
Step 325: 208980 + 645 = 209625
Step 326: 209625 + 645 = 210270
Step 327: 210270 + 645 = 210915
Step 328: 210915 + 645 = 211560
Step 329: 211560 + 645 = 212205
Step 330: 212205 + 645 = 212850
Step 331: 212850 + 645 = 213495
Step 332: 213495 + 645 = 214140
Step 333: 214140 + 645 = 214785
Step 334: 214785 + 645 = 215430
Step 335: 215430 + 645 = 216075
Step 336: 216075 + 645 = 216720
Step 337: 216720 + 645 = 217365
Step 338: 217365 + 645 = 218010
Step 339: 218010 + 645 = 218655
Step 340: 218655 + 645 = 219300
Step 341: 219300 + 645 = 219945
Step 342: 219945 + 645 = 220590
Step 343: 220590 + 645 = 221235
Step 344: 221235 + 645 = 221880
Step 345: 221880 + 645 = 222525
Step 346: 222525 + 645 = 223170
Step 347: 223170 + 645 = 223815
Step 348: 223815 + 645 = 224460
Step 349: 224460 + 645 = 225105
Step 350: 225105 + 645 = 225750
Step 351: 225750 + 645 = 226395
Step 352: 226395 + 645 = 227040
Step 353: 227040 + 645 = 227685
Step 354: 227685 + 645 = 228330
Step 355: 228330 + 645 = 228975
Step 356: 228975 + 645 = 229620
Step 357: 229620 + 645 = 230265
Step 358: 230265 + 645 = 230910
Step 359: 230910 + 645 = 231555
Step 360: 231555 + 645 = 232200
Step 361: 232200 + 645 = 232845
Step 362: 232845 + 645 = 233490
Step 363: 233490 + 645 = 234135
Step 364: 234135 + 645 = 234780
Step 365: 234780 + 645 = 235425
Step 366: 235425 + 645 = 236070
Step 367: 236070 + 645 = 236715
Step 368: 236715 + 645 = 237360
Step 369: 237360 + 645 = 238005
Step 370: 238005 + 645 = 238650
Step 371: 238650 + 645 = 239295
Step 372: 239295 + 645 = 239940
Step 373: 239940 + 645 = 240585
Step 374: 240585 + 645 = 241230
Step 375: 241230 + 645 = 241875
Step 376: 241875 + 645 = 242520
Step 377: 242520 + 645 = 243165
Step 378: 243165 + 645 = 243810
Step 379: 243810 + 645 = 244455
Step 380: 244455 + 645 = 245100
Step 381: 245100 + 645 = 245745
Step 382: 245745 + 645 = 246390
Step 383: 246390 + 645 = 247035
Step 384: 247035 + 645 = 247680
Step 385: 247680 + 645 = 248325
Step 386: 248325 + 645 = 248970
Step 387: 248970 + 645 = 249615
Step 388: 249615 + 645 = 250260
Step 389: 250260 + 645 = 250905
Step 390: 250905 + 645 = 251550
Step 391: 251550 + 645 = 252195
Step 392: 252195 + 645 = 252840
Step 393: 252840 + 645 = 253485
Step 394: 253485 + 645 = 254130
Step 395: 254130 + 645 = 254775
Step 396: 254775 + 645 = 255420
Step 397: 255420 + 645 = 256065
Step 398: 256065 + 645 = 256710
Step 399: 256710 + 645 = 257355
Step 400: 257355 + 645 = 258000
Step 401: 258000 + 645 = 258645
Step 402: 258645 + 645 = 259290
Step 403: 259290 + 645 = 259935
Step 404: 259935 + 645 = 260580
Step 405: 260580 + 645 = 261225
Step 406: 261225 + 645 = 261870
Step 407: 261870 + 645 = 262515
Step 408: 262515 + 645 = 263160
Step 409: 263160 + 645 = 263805
Step 410: 263805 + 645 = 264450
Step 411: 264450 + 645 = 265095
Step 412: 265095 + 645 = 265740
Step 413: 265740 + 645 = 266385
Step 414: 266385 + 645 = 267030
Step 415: 267030 + 645 = 267675
Step 416: 267675 + 645 = 268320
Step 417: 268320 + 645 = 268965
Step 418: 268965 + 645 = 269610
Step 419: 269610 + 645 = 270255
Step 420: 270255 + 645 = 270900
Step 421: 270900 + 645 = 271545
Step 422: 271545 + 645 = 272190
Step 423: 272190 + 645 = 272835
Step 424: 272835 + 645 = 273480
Step 425: 273480 + 645 = 274125
Step 426: 274125 + 645 = 274770
Step 427: 274770 + 645 = 275415
Step 428: 275415 + 645 = 276060
Step 429: 276060 + 645 = 276705
Step 430: 276705 + 645 = 277350
Step 431: 277350 + 645 = 277995
Step 432: 277995 + 645 = 278640
Step 433: 278640 + 645 = 279285
Step 434: 279285 + 645 = 279930
Step 435: 279930 + 645 = 280575
Step 436: 280575 + 645 = 281220
Step 437: 281220 + 645 = 281865
Step 438: 281865 + 645 = 282510
Step 439: 282510 + 645 = 283155
Step 440: 283155 + 645 = 283800
Step 441: 283800 + 645 = 284445
Step 442: 284445 + 645 = 285090
Step 443: 285090 + 645 = 285735
Step 444: 285735 + 645 = 286380
Step 445: 286380 + 645 = 287025
Step 446: 287025 + 645 = 287670
Step 447: 287670 + 645 = 288315
Step 448: 288315 + 645 = 288960
Step 449: 288960 + 645 = 289605
Step 450: 289605 + 645 = 290250
Step 451: 290250 + 645 = 290895
Step 452: 290895 + 645 = 291540
Step 453: 291540 + 645 = 292185
Step 454: 292185 + 645 = 292830
Step 455: 292830 + 645 = 293475
Step 456: 293475 + 645 = 294120
Step 457: 294120 + 645 = 294765
Step 458: 294765 + 645 = 295410
Step 459: 295410 + 645 = 296055
Step 460: 296055 + 645 = 296700
Step 461: 296700 + 645 = 297345
Step 462: 297345 + 645 = 297990
Step 463: 297990 + 645 = 298635
Step 464: 298635 + 645 = 299280
Step 465: 299280 + 645 = 299925
Step 466: 299925 + 645 = 300570
Step 467: 300570 + 645 = 301215
Step 468: 301215 + 645 = 301860
Step 469: 301860 + 645 = 302505
Step 470: 302505 + 645 = 303150
Step 471: 303150 + 645 = 303795
Step 472: 303795 + 645 = 304440
Step 473: 304440 + 645 = 305085
Step 474: 305085 + 645 = 305730
Step 475: 305730 + 645 = 306375
Step 476: 306375 + 645 = 307020
Step 477: 307020 + 645 = 307665
Step 478: 307665 + 645 = 308310
Step 479: 308310 + 645 = 308955
Step 480: 308955 + 645 = 309600
Step 481: 309600 + 645 = 310245
Step 482: 310245 + 645 = 310890
Step 483: 310890 + 645 = 311535
Step 484: 311535 + 645 = 312180
Step 485: 312180 + 645 = 312825
Step 486: 312825 + 645 = 313470
Step 487: 313470 + 645 = 314115
Step 488: 314115 + 645 = 314760
Step 489: 314760 + 645 = 315405
Step 490: 315405 + 645 = 316050
Step 491: 316050 + 645 = 316695
Step 492: 316695 + 645 = 317340
Step 493: 317340 + 645 = 317985
Step 494: 317985 + 645 = 318630
Step 495: 318630 + 645 = 319275
Step 496: 319275 + 645 = 319920
Step 497: 319920 + 645 = 320565
Step 498: 320565 + 645 = 321210

So, 645*498 = 321210