OK, let's crack this. We're given 343 and our task is to multiply it by 255. Essentially, we'll be adding 343 to itself 255 times.
Step 1: 0 + 343 = 343
Step 2: 343 + 343 = 686
Step 3: 686 + 343 = 1029
Step 4: 1029 + 343 = 1372
Step 5: 1372 + 343 = 1715
Step 6: 1715 + 343 = 2058
Step 7: 2058 + 343 = 2401
Step 8: 2401 + 343 = 2744
Step 9: 2744 + 343 = 3087
Step 10: 3087 + 343 = 3430
Step 11: 3430 + 343 = 3773
Step 12: 3773 + 343 = 4116
Step 13: 4116 + 343 = 4459
Step 14: 4459 + 343 = 4802
Step 15: 4802 + 343 = 5145
Step 16: 5145 + 343 = 5488
Step 17: 5488 + 343 = 5831
Step 18: 5831 + 343 = 6174
Step 19: 6174 + 343 = 6517
Step 20: 6517 + 343 = 6860
Step 21: 6860 + 343 = 7203
Step 22: 7203 + 343 = 7546
Step 23: 7546 + 343 = 7889
Step 24: 7889 + 343 = 8232
Step 25: 8232 + 343 = 8575
Step 26: 8575 + 343 = 8918
Step 27: 8918 + 343 = 9261
Step 28: 9261 + 343 = 9604
Step 29: 9604 + 343 = 9947
Step 30: 9947 + 343 = 10290
Step 31: 10290 + 343 = 10633
Step 32: 10633 + 343 = 10976
Step 33: 10976 + 343 = 11319
Step 34: 11319 + 343 = 11662
Step 35: 11662 + 343 = 12005
Step 36: 12005 + 343 = 12348
Step 37: 12348 + 343 = 12691
Step 38: 12691 + 343 = 13034
Step 39: 13034 + 343 = 13377
Step 40: 13377 + 343 = 13720
Step 41: 13720 + 343 = 14063
Step 42: 14063 + 343 = 14406
Step 43: 14406 + 343 = 14749
Step 44: 14749 + 343 = 15092
Step 45: 15092 + 343 = 15435
Step 46: 15435 + 343 = 15778
Step 47: 15778 + 343 = 16121
Step 48: 16121 + 343 = 16464
Step 49: 16464 + 343 = 16807
Step 50: 16807 + 343 = 17150
Step 51: 17150 + 343 = 17493
Step 52: 17493 + 343 = 17836
Step 53: 17836 + 343 = 18179
Step 54: 18179 + 343 = 18522
Step 55: 18522 + 343 = 18865
Step 56: 18865 + 343 = 19208
Step 57: 19208 + 343 = 19551
Step 58: 19551 + 343 = 19894
Step 59: 19894 + 343 = 20237
Step 60: 20237 + 343 = 20580
Step 61: 20580 + 343 = 20923
Step 62: 20923 + 343 = 21266
Step 63: 21266 + 343 = 21609
Step 64: 21609 + 343 = 21952
Step 65: 21952 + 343 = 22295
Step 66: 22295 + 343 = 22638
Step 67: 22638 + 343 = 22981
Step 68: 22981 + 343 = 23324
Step 69: 23324 + 343 = 23667
Step 70: 23667 + 343 = 24010
Step 71: 24010 + 343 = 24353
Step 72: 24353 + 343 = 24696
Step 73: 24696 + 343 = 25039
Step 74: 25039 + 343 = 25382
Step 75: 25382 + 343 = 25725
Step 76: 25725 + 343 = 26068
Step 77: 26068 + 343 = 26411
Step 78: 26411 + 343 = 26754
Step 79: 26754 + 343 = 27097
Step 80: 27097 + 343 = 27440
Step 81: 27440 + 343 = 27783
Step 82: 27783 + 343 = 28126
Step 83: 28126 + 343 = 28469
Step 84: 28469 + 343 = 28812
Step 85: 28812 + 343 = 29155
Step 86: 29155 + 343 = 29498
Step 87: 29498 + 343 = 29841
Step 88: 29841 + 343 = 30184
Step 89: 30184 + 343 = 30527
Step 90: 30527 + 343 = 30870
Step 91: 30870 + 343 = 31213
Step 92: 31213 + 343 = 31556
Step 93: 31556 + 343 = 31899
Step 94: 31899 + 343 = 32242
Step 95: 32242 + 343 = 32585
Step 96: 32585 + 343 = 32928
Step 97: 32928 + 343 = 33271
Step 98: 33271 + 343 = 33614
Step 99: 33614 + 343 = 33957
Step 100: 33957 + 343 = 34300
Step 101: 34300 + 343 = 34643
Step 102: 34643 + 343 = 34986
Step 103: 34986 + 343 = 35329
Step 104: 35329 + 343 = 35672
Step 105: 35672 + 343 = 36015
Step 106: 36015 + 343 = 36358
Step 107: 36358 + 343 = 36701
Step 108: 36701 + 343 = 37044
Step 109: 37044 + 343 = 37387
Step 110: 37387 + 343 = 37730
Step 111: 37730 + 343 = 38073
Step 112: 38073 + 343 = 38416
Step 113: 38416 + 343 = 38759
Step 114: 38759 + 343 = 39102
Step 115: 39102 + 343 = 39445
Step 116: 39445 + 343 = 39788
Step 117: 39788 + 343 = 40131
Step 118: 40131 + 343 = 40474
Step 119: 40474 + 343 = 40817
Step 120: 40817 + 343 = 41160
Step 121: 41160 + 343 = 41503
Step 122: 41503 + 343 = 41846
Step 123: 41846 + 343 = 42189
Step 124: 42189 + 343 = 42532
Step 125: 42532 + 343 = 42875
Step 126: 42875 + 343 = 43218
Step 127: 43218 + 343 = 43561
Step 128: 43561 + 343 = 43904
Step 129: 43904 + 343 = 44247
Step 130: 44247 + 343 = 44590
Step 131: 44590 + 343 = 44933
Step 132: 44933 + 343 = 45276
Step 133: 45276 + 343 = 45619
Step 134: 45619 + 343 = 45962
Step 135: 45962 + 343 = 46305
Step 136: 46305 + 343 = 46648
Step 137: 46648 + 343 = 46991
Step 138: 46991 + 343 = 47334
Step 139: 47334 + 343 = 47677
Step 140: 47677 + 343 = 48020
Step 141: 48020 + 343 = 48363
Step 142: 48363 + 343 = 48706
Step 143: 48706 + 343 = 49049
Step 144: 49049 + 343 = 49392
Step 145: 49392 + 343 = 49735
Step 146: 49735 + 343 = 50078
Step 147: 50078 + 343 = 50421
Step 148: 50421 + 343 = 50764
Step 149: 50764 + 343 = 51107
Step 150: 51107 + 343 = 51450
Step 151: 51450 + 343 = 51793
Step 152: 51793 + 343 = 52136
Step 153: 52136 + 343 = 52479
Step 154: 52479 + 343 = 52822
Step 155: 52822 + 343 = 53165
Step 156: 53165 + 343 = 53508
Step 157: 53508 + 343 = 53851
Step 158: 53851 + 343 = 54194
Step 159: 54194 + 343 = 54537
Step 160: 54537 + 343 = 54880
Step 161: 54880 + 343 = 55223
Step 162: 55223 + 343 = 55566
Step 163: 55566 + 343 = 55909
Step 164: 55909 + 343 = 56252
Step 165: 56252 + 343 = 56595
Step 166: 56595 + 343 = 56938
Step 167: 56938 + 343 = 57281
Step 168: 57281 + 343 = 57624
Step 169: 57624 + 343 = 57967
Step 170: 57967 + 343 = 58310
Step 171: 58310 + 343 = 58653
Step 172: 58653 + 343 = 58996
Step 173: 58996 + 343 = 59339
Step 174: 59339 + 343 = 59682
Step 175: 59682 + 343 = 60025
Step 176: 60025 + 343 = 60368
Step 177: 60368 + 343 = 60711
Step 178: 60711 + 343 = 61054
Step 179: 61054 + 343 = 61397
Step 180: 61397 + 343 = 61740
Step 181: 61740 + 343 = 62083
Step 182: 62083 + 343 = 62426
Step 183: 62426 + 343 = 62769
Step 184: 62769 + 343 = 63112
Step 185: 63112 + 343 = 63455
Step 186: 63455 + 343 = 63798
Step 187: 63798 + 343 = 64141
Step 188: 64141 + 343 = 64484
Step 189: 64484 + 343 = 64827
Step 190: 64827 + 343 = 65170
Step 191: 65170 + 343 = 65513
Step 192: 65513 + 343 = 65856
Step 193: 65856 + 343 = 66199
Step 194: 66199 + 343 = 66542
Step 195: 66542 + 343 = 66885
Step 196: 66885 + 343 = 67228
Step 197: 67228 + 343 = 67571
Step 198: 67571 + 343 = 67914
Step 199: 67914 + 343 = 68257
Step 200: 68257 + 343 = 68600
Step 201: 68600 + 343 = 68943
Step 202: 68943 + 343 = 69286
Step 203: 69286 + 343 = 69629
Step 204: 69629 + 343 = 69972
Step 205: 69972 + 343 = 70315
Step 206: 70315 + 343 = 70658
Step 207: 70658 + 343 = 71001
Step 208: 71001 + 343 = 71344
Step 209: 71344 + 343 = 71687
Step 210: 71687 + 343 = 72030
Step 211: 72030 + 343 = 72373
Step 212: 72373 + 343 = 72716
Step 213: 72716 + 343 = 73059
Step 214: 73059 + 343 = 73402
Step 215: 73402 + 343 = 73745
Step 216: 73745 + 343 = 74088
Step 217: 74088 + 343 = 74431
Step 218: 74431 + 343 = 74774
Step 219: 74774 + 343 = 75117
Step 220: 75117 + 343 = 75460
Step 221: 75460 + 343 = 75803
Step 222: 75803 + 343 = 76146
Step 223: 76146 + 343 = 76489
Step 224: 76489 + 343 = 76832
Step 225: 76832 + 343 = 77175
Step 226: 77175 + 343 = 77518
Step 227: 77518 + 343 = 77861
Step 228: 77861 + 343 = 78204
Step 229: 78204 + 343 = 78547
Step 230: 78547 + 343 = 78890
Step 231: 78890 + 343 = 79233
Step 232: 79233 + 343 = 79576
Step 233: 79576 + 343 = 79919
Step 234: 79919 + 343 = 80262
Step 235: 80262 + 343 = 80605
Step 236: 80605 + 343 = 80948
Step 237: 80948 + 343 = 81291
Step 238: 81291 + 343 = 81634
Step 239: 81634 + 343 = 81977
Step 240: 81977 + 343 = 82320
Step 241: 82320 + 343 = 82663
Step 242: 82663 + 343 = 83006
Step 243: 83006 + 343 = 83349
Step 244: 83349 + 343 = 83692
Step 245: 83692 + 343 = 84035
Step 246: 84035 + 343 = 84378
Step 247: 84378 + 343 = 84721
Step 248: 84721 + 343 = 85064
Step 249: 85064 + 343 = 85407
Step 250: 85407 + 343 = 85750
Step 251: 85750 + 343 = 86093
Step 252: 86093 + 343 = 86436
Step 253: 86436 + 343 = 86779
Step 254: 86779 + 343 = 87122
Step 255: 87122 + 343 = 87465

So, 343*255 = 87465