OK, let's work through this together. We're starting with 681 and we're going to multiply it by 309, which means we add 681 to itself 309 times.
Step 1: 0 + 681 = 681
Step 2: 681 + 681 = 1362
Step 3: 1362 + 681 = 2043
Step 4: 2043 + 681 = 2724
Step 5: 2724 + 681 = 3405
Step 6: 3405 + 681 = 4086
Step 7: 4086 + 681 = 4767
Step 8: 4767 + 681 = 5448
Step 9: 5448 + 681 = 6129
Step 10: 6129 + 681 = 6810
Step 11: 6810 + 681 = 7491
Step 12: 7491 + 681 = 8172
Step 13: 8172 + 681 = 8853
Step 14: 8853 + 681 = 9534
Step 15: 9534 + 681 = 10215
Step 16: 10215 + 681 = 10896
Step 17: 10896 + 681 = 11577
Step 18: 11577 + 681 = 12258
Step 19: 12258 + 681 = 12939
Step 20: 12939 + 681 = 13620
Step 21: 13620 + 681 = 14301
Step 22: 14301 + 681 = 14982
Step 23: 14982 + 681 = 15663
Step 24: 15663 + 681 = 16344
Step 25: 16344 + 681 = 17025
Step 26: 17025 + 681 = 17706
Step 27: 17706 + 681 = 18387
Step 28: 18387 + 681 = 19068
Step 29: 19068 + 681 = 19749
Step 30: 19749 + 681 = 20430
Step 31: 20430 + 681 = 21111
Step 32: 21111 + 681 = 21792
Step 33: 21792 + 681 = 22473
Step 34: 22473 + 681 = 23154
Step 35: 23154 + 681 = 23835
Step 36: 23835 + 681 = 24516
Step 37: 24516 + 681 = 25197
Step 38: 25197 + 681 = 25878
Step 39: 25878 + 681 = 26559
Step 40: 26559 + 681 = 27240
Step 41: 27240 + 681 = 27921
Step 42: 27921 + 681 = 28602
Step 43: 28602 + 681 = 29283
Step 44: 29283 + 681 = 29964
Step 45: 29964 + 681 = 30645
Step 46: 30645 + 681 = 31326
Step 47: 31326 + 681 = 32007
Step 48: 32007 + 681 = 32688
Step 49: 32688 + 681 = 33369
Step 50: 33369 + 681 = 34050
Step 51: 34050 + 681 = 34731
Step 52: 34731 + 681 = 35412
Step 53: 35412 + 681 = 36093
Step 54: 36093 + 681 = 36774
Step 55: 36774 + 681 = 37455
Step 56: 37455 + 681 = 38136
Step 57: 38136 + 681 = 38817
Step 58: 38817 + 681 = 39498
Step 59: 39498 + 681 = 40179
Step 60: 40179 + 681 = 40860
Step 61: 40860 + 681 = 41541
Step 62: 41541 + 681 = 42222
Step 63: 42222 + 681 = 42903
Step 64: 42903 + 681 = 43584
Step 65: 43584 + 681 = 44265
Step 66: 44265 + 681 = 44946
Step 67: 44946 + 681 = 45627
Step 68: 45627 + 681 = 46308
Step 69: 46308 + 681 = 46989
Step 70: 46989 + 681 = 47670
Step 71: 47670 + 681 = 48351
Step 72: 48351 + 681 = 49032
Step 73: 49032 + 681 = 49713
Step 74: 49713 + 681 = 50394
Step 75: 50394 + 681 = 51075
Step 76: 51075 + 681 = 51756
Step 77: 51756 + 681 = 52437
Step 78: 52437 + 681 = 53118
Step 79: 53118 + 681 = 53799
Step 80: 53799 + 681 = 54480
Step 81: 54480 + 681 = 55161
Step 82: 55161 + 681 = 55842
Step 83: 55842 + 681 = 56523
Step 84: 56523 + 681 = 57204
Step 85: 57204 + 681 = 57885
Step 86: 57885 + 681 = 58566
Step 87: 58566 + 681 = 59247
Step 88: 59247 + 681 = 59928
Step 89: 59928 + 681 = 60609
Step 90: 60609 + 681 = 61290
Step 91: 61290 + 681 = 61971
Step 92: 61971 + 681 = 62652
Step 93: 62652 + 681 = 63333
Step 94: 63333 + 681 = 64014
Step 95: 64014 + 681 = 64695
Step 96: 64695 + 681 = 65376
Step 97: 65376 + 681 = 66057
Step 98: 66057 + 681 = 66738
Step 99: 66738 + 681 = 67419
Step 100: 67419 + 681 = 68100
Step 101: 68100 + 681 = 68781
Step 102: 68781 + 681 = 69462
Step 103: 69462 + 681 = 70143
Step 104: 70143 + 681 = 70824
Step 105: 70824 + 681 = 71505
Step 106: 71505 + 681 = 72186
Step 107: 72186 + 681 = 72867
Step 108: 72867 + 681 = 73548
Step 109: 73548 + 681 = 74229
Step 110: 74229 + 681 = 74910
Step 111: 74910 + 681 = 75591
Step 112: 75591 + 681 = 76272
Step 113: 76272 + 681 = 76953
Step 114: 76953 + 681 = 77634
Step 115: 77634 + 681 = 78315
Step 116: 78315 + 681 = 78996
Step 117: 78996 + 681 = 79677
Step 118: 79677 + 681 = 80358
Step 119: 80358 + 681 = 81039
Step 120: 81039 + 681 = 81720
Step 121: 81720 + 681 = 82401
Step 122: 82401 + 681 = 83082
Step 123: 83082 + 681 = 83763
Step 124: 83763 + 681 = 84444
Step 125: 84444 + 681 = 85125
Step 126: 85125 + 681 = 85806
Step 127: 85806 + 681 = 86487
Step 128: 86487 + 681 = 87168
Step 129: 87168 + 681 = 87849
Step 130: 87849 + 681 = 88530
Step 131: 88530 + 681 = 89211
Step 132: 89211 + 681 = 89892
Step 133: 89892 + 681 = 90573
Step 134: 90573 + 681 = 91254
Step 135: 91254 + 681 = 91935
Step 136: 91935 + 681 = 92616
Step 137: 92616 + 681 = 93297
Step 138: 93297 + 681 = 93978
Step 139: 93978 + 681 = 94659
Step 140: 94659 + 681 = 95340
Step 141: 95340 + 681 = 96021
Step 142: 96021 + 681 = 96702
Step 143: 96702 + 681 = 97383
Step 144: 97383 + 681 = 98064
Step 145: 98064 + 681 = 98745
Step 146: 98745 + 681 = 99426
Step 147: 99426 + 681 = 100107
Step 148: 100107 + 681 = 100788
Step 149: 100788 + 681 = 101469
Step 150: 101469 + 681 = 102150
Step 151: 102150 + 681 = 102831
Step 152: 102831 + 681 = 103512
Step 153: 103512 + 681 = 104193
Step 154: 104193 + 681 = 104874
Step 155: 104874 + 681 = 105555
Step 156: 105555 + 681 = 106236
Step 157: 106236 + 681 = 106917
Step 158: 106917 + 681 = 107598
Step 159: 107598 + 681 = 108279
Step 160: 108279 + 681 = 108960
Step 161: 108960 + 681 = 109641
Step 162: 109641 + 681 = 110322
Step 163: 110322 + 681 = 111003
Step 164: 111003 + 681 = 111684
Step 165: 111684 + 681 = 112365
Step 166: 112365 + 681 = 113046
Step 167: 113046 + 681 = 113727
Step 168: 113727 + 681 = 114408
Step 169: 114408 + 681 = 115089
Step 170: 115089 + 681 = 115770
Step 171: 115770 + 681 = 116451
Step 172: 116451 + 681 = 117132
Step 173: 117132 + 681 = 117813
Step 174: 117813 + 681 = 118494
Step 175: 118494 + 681 = 119175
Step 176: 119175 + 681 = 119856
Step 177: 119856 + 681 = 120537
Step 178: 120537 + 681 = 121218
Step 179: 121218 + 681 = 121899
Step 180: 121899 + 681 = 122580
Step 181: 122580 + 681 = 123261
Step 182: 123261 + 681 = 123942
Step 183: 123942 + 681 = 124623
Step 184: 124623 + 681 = 125304
Step 185: 125304 + 681 = 125985
Step 186: 125985 + 681 = 126666
Step 187: 126666 + 681 = 127347
Step 188: 127347 + 681 = 128028
Step 189: 128028 + 681 = 128709
Step 190: 128709 + 681 = 129390
Step 191: 129390 + 681 = 130071
Step 192: 130071 + 681 = 130752
Step 193: 130752 + 681 = 131433
Step 194: 131433 + 681 = 132114
Step 195: 132114 + 681 = 132795
Step 196: 132795 + 681 = 133476
Step 197: 133476 + 681 = 134157
Step 198: 134157 + 681 = 134838
Step 199: 134838 + 681 = 135519
Step 200: 135519 + 681 = 136200
Step 201: 136200 + 681 = 136881
Step 202: 136881 + 681 = 137562
Step 203: 137562 + 681 = 138243
Step 204: 138243 + 681 = 138924
Step 205: 138924 + 681 = 139605
Step 206: 139605 + 681 = 140286
Step 207: 140286 + 681 = 140967
Step 208: 140967 + 681 = 141648
Step 209: 141648 + 681 = 142329
Step 210: 142329 + 681 = 143010
Step 211: 143010 + 681 = 143691
Step 212: 143691 + 681 = 144372
Step 213: 144372 + 681 = 145053
Step 214: 145053 + 681 = 145734
Step 215: 145734 + 681 = 146415
Step 216: 146415 + 681 = 147096
Step 217: 147096 + 681 = 147777
Step 218: 147777 + 681 = 148458
Step 219: 148458 + 681 = 149139
Step 220: 149139 + 681 = 149820
Step 221: 149820 + 681 = 150501
Step 222: 150501 + 681 = 151182
Step 223: 151182 + 681 = 151863
Step 224: 151863 + 681 = 152544
Step 225: 152544 + 681 = 153225
Step 226: 153225 + 681 = 153906
Step 227: 153906 + 681 = 154587
Step 228: 154587 + 681 = 155268
Step 229: 155268 + 681 = 155949
Step 230: 155949 + 681 = 156630
Step 231: 156630 + 681 = 157311
Step 232: 157311 + 681 = 157992
Step 233: 157992 + 681 = 158673
Step 234: 158673 + 681 = 159354
Step 235: 159354 + 681 = 160035
Step 236: 160035 + 681 = 160716
Step 237: 160716 + 681 = 161397
Step 238: 161397 + 681 = 162078
Step 239: 162078 + 681 = 162759
Step 240: 162759 + 681 = 163440
Step 241: 163440 + 681 = 164121
Step 242: 164121 + 681 = 164802
Step 243: 164802 + 681 = 165483
Step 244: 165483 + 681 = 166164
Step 245: 166164 + 681 = 166845
Step 246: 166845 + 681 = 167526
Step 247: 167526 + 681 = 168207
Step 248: 168207 + 681 = 168888
Step 249: 168888 + 681 = 169569
Step 250: 169569 + 681 = 170250
Step 251: 170250 + 681 = 170931
Step 252: 170931 + 681 = 171612
Step 253: 171612 + 681 = 172293
Step 254: 172293 + 681 = 172974
Step 255: 172974 + 681 = 173655
Step 256: 173655 + 681 = 174336
Step 257: 174336 + 681 = 175017
Step 258: 175017 + 681 = 175698
Step 259: 175698 + 681 = 176379
Step 260: 176379 + 681 = 177060
Step 261: 177060 + 681 = 177741
Step 262: 177741 + 681 = 178422
Step 263: 178422 + 681 = 179103
Step 264: 179103 + 681 = 179784
Step 265: 179784 + 681 = 180465
Step 266: 180465 + 681 = 181146
Step 267: 181146 + 681 = 181827
Step 268: 181827 + 681 = 182508
Step 269: 182508 + 681 = 183189
Step 270: 183189 + 681 = 183870
Step 271: 183870 + 681 = 184551
Step 272: 184551 + 681 = 185232
Step 273: 185232 + 681 = 185913
Step 274: 185913 + 681 = 186594
Step 275: 186594 + 681 = 187275
Step 276: 187275 + 681 = 187956
Step 277: 187956 + 681 = 188637
Step 278: 188637 + 681 = 189318
Step 279: 189318 + 681 = 189999
Step 280: 189999 + 681 = 190680
Step 281: 190680 + 681 = 191361
Step 282: 191361 + 681 = 192042
Step 283: 192042 + 681 = 192723
Step 284: 192723 + 681 = 193404
Step 285: 193404 + 681 = 194085
Step 286: 194085 + 681 = 194766
Step 287: 194766 + 681 = 195447
Step 288: 195447 + 681 = 196128
Step 289: 196128 + 681 = 196809
Step 290: 196809 + 681 = 197490
Step 291: 197490 + 681 = 198171
Step 292: 198171 + 681 = 198852
Step 293: 198852 + 681 = 199533
Step 294: 199533 + 681 = 200214
Step 295: 200214 + 681 = 200895
Step 296: 200895 + 681 = 201576
Step 297: 201576 + 681 = 202257
Step 298: 202257 + 681 = 202938
Step 299: 202938 + 681 = 203619
Step 300: 203619 + 681 = 204300
Step 301: 204300 + 681 = 204981
Step 302: 204981 + 681 = 205662
Step 303: 205662 + 681 = 206343
Step 304: 206343 + 681 = 207024
Step 305: 207024 + 681 = 207705
Step 306: 207705 + 681 = 208386
Step 307: 208386 + 681 = 209067
Step 308: 209067 + 681 = 209748
Step 309: 209748 + 681 = 210429

So, 681*309 = 210429