Alright, let's solve this math problem step by step. First, we have the number 646. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 308. So, we're going to take the number 646 and add it to itself 308 times.
Step 1: 0 + 646 = 646
Step 2: 646 + 646 = 1292
Step 3: 1292 + 646 = 1938
Step 4: 1938 + 646 = 2584
Step 5: 2584 + 646 = 3230
Step 6: 3230 + 646 = 3876
Step 7: 3876 + 646 = 4522
Step 8: 4522 + 646 = 5168
Step 9: 5168 + 646 = 5814
Step 10: 5814 + 646 = 6460
Step 11: 6460 + 646 = 7106
Step 12: 7106 + 646 = 7752
Step 13: 7752 + 646 = 8398
Step 14: 8398 + 646 = 9044
Step 15: 9044 + 646 = 9690
Step 16: 9690 + 646 = 10336
Step 17: 10336 + 646 = 10982
Step 18: 10982 + 646 = 11628
Step 19: 11628 + 646 = 12274
Step 20: 12274 + 646 = 12920
Step 21: 12920 + 646 = 13566
Step 22: 13566 + 646 = 14212
Step 23: 14212 + 646 = 14858
Step 24: 14858 + 646 = 15504
Step 25: 15504 + 646 = 16150
Step 26: 16150 + 646 = 16796
Step 27: 16796 + 646 = 17442
Step 28: 17442 + 646 = 18088
Step 29: 18088 + 646 = 18734
Step 30: 18734 + 646 = 19380
Step 31: 19380 + 646 = 20026
Step 32: 20026 + 646 = 20672
Step 33: 20672 + 646 = 21318
Step 34: 21318 + 646 = 21964
Step 35: 21964 + 646 = 22610
Step 36: 22610 + 646 = 23256
Step 37: 23256 + 646 = 23902
Step 38: 23902 + 646 = 24548
Step 39: 24548 + 646 = 25194
Step 40: 25194 + 646 = 25840
Step 41: 25840 + 646 = 26486
Step 42: 26486 + 646 = 27132
Step 43: 27132 + 646 = 27778
Step 44: 27778 + 646 = 28424
Step 45: 28424 + 646 = 29070
Step 46: 29070 + 646 = 29716
Step 47: 29716 + 646 = 30362
Step 48: 30362 + 646 = 31008
Step 49: 31008 + 646 = 31654
Step 50: 31654 + 646 = 32300
Step 51: 32300 + 646 = 32946
Step 52: 32946 + 646 = 33592
Step 53: 33592 + 646 = 34238
Step 54: 34238 + 646 = 34884
Step 55: 34884 + 646 = 35530
Step 56: 35530 + 646 = 36176
Step 57: 36176 + 646 = 36822
Step 58: 36822 + 646 = 37468
Step 59: 37468 + 646 = 38114
Step 60: 38114 + 646 = 38760
Step 61: 38760 + 646 = 39406
Step 62: 39406 + 646 = 40052
Step 63: 40052 + 646 = 40698
Step 64: 40698 + 646 = 41344
Step 65: 41344 + 646 = 41990
Step 66: 41990 + 646 = 42636
Step 67: 42636 + 646 = 43282
Step 68: 43282 + 646 = 43928
Step 69: 43928 + 646 = 44574
Step 70: 44574 + 646 = 45220
Step 71: 45220 + 646 = 45866
Step 72: 45866 + 646 = 46512
Step 73: 46512 + 646 = 47158
Step 74: 47158 + 646 = 47804
Step 75: 47804 + 646 = 48450
Step 76: 48450 + 646 = 49096
Step 77: 49096 + 646 = 49742
Step 78: 49742 + 646 = 50388
Step 79: 50388 + 646 = 51034
Step 80: 51034 + 646 = 51680
Step 81: 51680 + 646 = 52326
Step 82: 52326 + 646 = 52972
Step 83: 52972 + 646 = 53618
Step 84: 53618 + 646 = 54264
Step 85: 54264 + 646 = 54910
Step 86: 54910 + 646 = 55556
Step 87: 55556 + 646 = 56202
Step 88: 56202 + 646 = 56848
Step 89: 56848 + 646 = 57494
Step 90: 57494 + 646 = 58140
Step 91: 58140 + 646 = 58786
Step 92: 58786 + 646 = 59432
Step 93: 59432 + 646 = 60078
Step 94: 60078 + 646 = 60724
Step 95: 60724 + 646 = 61370
Step 96: 61370 + 646 = 62016
Step 97: 62016 + 646 = 62662
Step 98: 62662 + 646 = 63308
Step 99: 63308 + 646 = 63954
Step 100: 63954 + 646 = 64600
Step 101: 64600 + 646 = 65246
Step 102: 65246 + 646 = 65892
Step 103: 65892 + 646 = 66538
Step 104: 66538 + 646 = 67184
Step 105: 67184 + 646 = 67830
Step 106: 67830 + 646 = 68476
Step 107: 68476 + 646 = 69122
Step 108: 69122 + 646 = 69768
Step 109: 69768 + 646 = 70414
Step 110: 70414 + 646 = 71060
Step 111: 71060 + 646 = 71706
Step 112: 71706 + 646 = 72352
Step 113: 72352 + 646 = 72998
Step 114: 72998 + 646 = 73644
Step 115: 73644 + 646 = 74290
Step 116: 74290 + 646 = 74936
Step 117: 74936 + 646 = 75582
Step 118: 75582 + 646 = 76228
Step 119: 76228 + 646 = 76874
Step 120: 76874 + 646 = 77520
Step 121: 77520 + 646 = 78166
Step 122: 78166 + 646 = 78812
Step 123: 78812 + 646 = 79458
Step 124: 79458 + 646 = 80104
Step 125: 80104 + 646 = 80750
Step 126: 80750 + 646 = 81396
Step 127: 81396 + 646 = 82042
Step 128: 82042 + 646 = 82688
Step 129: 82688 + 646 = 83334
Step 130: 83334 + 646 = 83980
Step 131: 83980 + 646 = 84626
Step 132: 84626 + 646 = 85272
Step 133: 85272 + 646 = 85918
Step 134: 85918 + 646 = 86564
Step 135: 86564 + 646 = 87210
Step 136: 87210 + 646 = 87856
Step 137: 87856 + 646 = 88502
Step 138: 88502 + 646 = 89148
Step 139: 89148 + 646 = 89794
Step 140: 89794 + 646 = 90440
Step 141: 90440 + 646 = 91086
Step 142: 91086 + 646 = 91732
Step 143: 91732 + 646 = 92378
Step 144: 92378 + 646 = 93024
Step 145: 93024 + 646 = 93670
Step 146: 93670 + 646 = 94316
Step 147: 94316 + 646 = 94962
Step 148: 94962 + 646 = 95608
Step 149: 95608 + 646 = 96254
Step 150: 96254 + 646 = 96900
Step 151: 96900 + 646 = 97546
Step 152: 97546 + 646 = 98192
Step 153: 98192 + 646 = 98838
Step 154: 98838 + 646 = 99484
Step 155: 99484 + 646 = 100130
Step 156: 100130 + 646 = 100776
Step 157: 100776 + 646 = 101422
Step 158: 101422 + 646 = 102068
Step 159: 102068 + 646 = 102714
Step 160: 102714 + 646 = 103360
Step 161: 103360 + 646 = 104006
Step 162: 104006 + 646 = 104652
Step 163: 104652 + 646 = 105298
Step 164: 105298 + 646 = 105944
Step 165: 105944 + 646 = 106590
Step 166: 106590 + 646 = 107236
Step 167: 107236 + 646 = 107882
Step 168: 107882 + 646 = 108528
Step 169: 108528 + 646 = 109174
Step 170: 109174 + 646 = 109820
Step 171: 109820 + 646 = 110466
Step 172: 110466 + 646 = 111112
Step 173: 111112 + 646 = 111758
Step 174: 111758 + 646 = 112404
Step 175: 112404 + 646 = 113050
Step 176: 113050 + 646 = 113696
Step 177: 113696 + 646 = 114342
Step 178: 114342 + 646 = 114988
Step 179: 114988 + 646 = 115634
Step 180: 115634 + 646 = 116280
Step 181: 116280 + 646 = 116926
Step 182: 116926 + 646 = 117572
Step 183: 117572 + 646 = 118218
Step 184: 118218 + 646 = 118864
Step 185: 118864 + 646 = 119510
Step 186: 119510 + 646 = 120156
Step 187: 120156 + 646 = 120802
Step 188: 120802 + 646 = 121448
Step 189: 121448 + 646 = 122094
Step 190: 122094 + 646 = 122740
Step 191: 122740 + 646 = 123386
Step 192: 123386 + 646 = 124032
Step 193: 124032 + 646 = 124678
Step 194: 124678 + 646 = 125324
Step 195: 125324 + 646 = 125970
Step 196: 125970 + 646 = 126616
Step 197: 126616 + 646 = 127262
Step 198: 127262 + 646 = 127908
Step 199: 127908 + 646 = 128554
Step 200: 128554 + 646 = 129200
Step 201: 129200 + 646 = 129846
Step 202: 129846 + 646 = 130492
Step 203: 130492 + 646 = 131138
Step 204: 131138 + 646 = 131784
Step 205: 131784 + 646 = 132430
Step 206: 132430 + 646 = 133076
Step 207: 133076 + 646 = 133722
Step 208: 133722 + 646 = 134368
Step 209: 134368 + 646 = 135014
Step 210: 135014 + 646 = 135660
Step 211: 135660 + 646 = 136306
Step 212: 136306 + 646 = 136952
Step 213: 136952 + 646 = 137598
Step 214: 137598 + 646 = 138244
Step 215: 138244 + 646 = 138890
Step 216: 138890 + 646 = 139536
Step 217: 139536 + 646 = 140182
Step 218: 140182 + 646 = 140828
Step 219: 140828 + 646 = 141474
Step 220: 141474 + 646 = 142120
Step 221: 142120 + 646 = 142766
Step 222: 142766 + 646 = 143412
Step 223: 143412 + 646 = 144058
Step 224: 144058 + 646 = 144704
Step 225: 144704 + 646 = 145350
Step 226: 145350 + 646 = 145996
Step 227: 145996 + 646 = 146642
Step 228: 146642 + 646 = 147288
Step 229: 147288 + 646 = 147934
Step 230: 147934 + 646 = 148580
Step 231: 148580 + 646 = 149226
Step 232: 149226 + 646 = 149872
Step 233: 149872 + 646 = 150518
Step 234: 150518 + 646 = 151164
Step 235: 151164 + 646 = 151810
Step 236: 151810 + 646 = 152456
Step 237: 152456 + 646 = 153102
Step 238: 153102 + 646 = 153748
Step 239: 153748 + 646 = 154394
Step 240: 154394 + 646 = 155040
Step 241: 155040 + 646 = 155686
Step 242: 155686 + 646 = 156332
Step 243: 156332 + 646 = 156978
Step 244: 156978 + 646 = 157624
Step 245: 157624 + 646 = 158270
Step 246: 158270 + 646 = 158916
Step 247: 158916 + 646 = 159562
Step 248: 159562 + 646 = 160208
Step 249: 160208 + 646 = 160854
Step 250: 160854 + 646 = 161500
Step 251: 161500 + 646 = 162146
Step 252: 162146 + 646 = 162792
Step 253: 162792 + 646 = 163438
Step 254: 163438 + 646 = 164084
Step 255: 164084 + 646 = 164730
Step 256: 164730 + 646 = 165376
Step 257: 165376 + 646 = 166022
Step 258: 166022 + 646 = 166668
Step 259: 166668 + 646 = 167314
Step 260: 167314 + 646 = 167960
Step 261: 167960 + 646 = 168606
Step 262: 168606 + 646 = 169252
Step 263: 169252 + 646 = 169898
Step 264: 169898 + 646 = 170544
Step 265: 170544 + 646 = 171190
Step 266: 171190 + 646 = 171836
Step 267: 171836 + 646 = 172482
Step 268: 172482 + 646 = 173128
Step 269: 173128 + 646 = 173774
Step 270: 173774 + 646 = 174420
Step 271: 174420 + 646 = 175066
Step 272: 175066 + 646 = 175712
Step 273: 175712 + 646 = 176358
Step 274: 176358 + 646 = 177004
Step 275: 177004 + 646 = 177650
Step 276: 177650 + 646 = 178296
Step 277: 178296 + 646 = 178942
Step 278: 178942 + 646 = 179588
Step 279: 179588 + 646 = 180234
Step 280: 180234 + 646 = 180880
Step 281: 180880 + 646 = 181526
Step 282: 181526 + 646 = 182172
Step 283: 182172 + 646 = 182818
Step 284: 182818 + 646 = 183464
Step 285: 183464 + 646 = 184110
Step 286: 184110 + 646 = 184756
Step 287: 184756 + 646 = 185402
Step 288: 185402 + 646 = 186048
Step 289: 186048 + 646 = 186694
Step 290: 186694 + 646 = 187340
Step 291: 187340 + 646 = 187986
Step 292: 187986 + 646 = 188632
Step 293: 188632 + 646 = 189278
Step 294: 189278 + 646 = 189924
Step 295: 189924 + 646 = 190570
Step 296: 190570 + 646 = 191216
Step 297: 191216 + 646 = 191862
Step 298: 191862 + 646 = 192508
Step 299: 192508 + 646 = 193154
Step 300: 193154 + 646 = 193800
Step 301: 193800 + 646 = 194446
Step 302: 194446 + 646 = 195092
Step 303: 195092 + 646 = 195738
Step 304: 195738 + 646 = 196384
Step 305: 196384 + 646 = 197030
Step 306: 197030 + 646 = 197676
Step 307: 197676 + 646 = 198322
Step 308: 198322 + 646 = 198968

So, 646*308 = 198968