Sure thing! We've got 339 and we're gonna multiply it by 400. That's the same as adding 339 to itself 400 times.
Step 1: 0 + 339 = 339
Step 2: 339 + 339 = 678
Step 3: 678 + 339 = 1017
Step 4: 1017 + 339 = 1356
Step 5: 1356 + 339 = 1695
Step 6: 1695 + 339 = 2034
Step 7: 2034 + 339 = 2373
Step 8: 2373 + 339 = 2712
Step 9: 2712 + 339 = 3051
Step 10: 3051 + 339 = 3390
Step 11: 3390 + 339 = 3729
Step 12: 3729 + 339 = 4068
Step 13: 4068 + 339 = 4407
Step 14: 4407 + 339 = 4746
Step 15: 4746 + 339 = 5085
Step 16: 5085 + 339 = 5424
Step 17: 5424 + 339 = 5763
Step 18: 5763 + 339 = 6102
Step 19: 6102 + 339 = 6441
Step 20: 6441 + 339 = 6780
Step 21: 6780 + 339 = 7119
Step 22: 7119 + 339 = 7458
Step 23: 7458 + 339 = 7797
Step 24: 7797 + 339 = 8136
Step 25: 8136 + 339 = 8475
Step 26: 8475 + 339 = 8814
Step 27: 8814 + 339 = 9153
Step 28: 9153 + 339 = 9492
Step 29: 9492 + 339 = 9831
Step 30: 9831 + 339 = 10170
Step 31: 10170 + 339 = 10509
Step 32: 10509 + 339 = 10848
Step 33: 10848 + 339 = 11187
Step 34: 11187 + 339 = 11526
Step 35: 11526 + 339 = 11865
Step 36: 11865 + 339 = 12204
Step 37: 12204 + 339 = 12543
Step 38: 12543 + 339 = 12882
Step 39: 12882 + 339 = 13221
Step 40: 13221 + 339 = 13560
Step 41: 13560 + 339 = 13899
Step 42: 13899 + 339 = 14238
Step 43: 14238 + 339 = 14577
Step 44: 14577 + 339 = 14916
Step 45: 14916 + 339 = 15255
Step 46: 15255 + 339 = 15594
Step 47: 15594 + 339 = 15933
Step 48: 15933 + 339 = 16272
Step 49: 16272 + 339 = 16611
Step 50: 16611 + 339 = 16950
Step 51: 16950 + 339 = 17289
Step 52: 17289 + 339 = 17628
Step 53: 17628 + 339 = 17967
Step 54: 17967 + 339 = 18306
Step 55: 18306 + 339 = 18645
Step 56: 18645 + 339 = 18984
Step 57: 18984 + 339 = 19323
Step 58: 19323 + 339 = 19662
Step 59: 19662 + 339 = 20001
Step 60: 20001 + 339 = 20340
Step 61: 20340 + 339 = 20679
Step 62: 20679 + 339 = 21018
Step 63: 21018 + 339 = 21357
Step 64: 21357 + 339 = 21696
Step 65: 21696 + 339 = 22035
Step 66: 22035 + 339 = 22374
Step 67: 22374 + 339 = 22713
Step 68: 22713 + 339 = 23052
Step 69: 23052 + 339 = 23391
Step 70: 23391 + 339 = 23730
Step 71: 23730 + 339 = 24069
Step 72: 24069 + 339 = 24408
Step 73: 24408 + 339 = 24747
Step 74: 24747 + 339 = 25086
Step 75: 25086 + 339 = 25425
Step 76: 25425 + 339 = 25764
Step 77: 25764 + 339 = 26103
Step 78: 26103 + 339 = 26442
Step 79: 26442 + 339 = 26781
Step 80: 26781 + 339 = 27120
Step 81: 27120 + 339 = 27459
Step 82: 27459 + 339 = 27798
Step 83: 27798 + 339 = 28137
Step 84: 28137 + 339 = 28476
Step 85: 28476 + 339 = 28815
Step 86: 28815 + 339 = 29154
Step 87: 29154 + 339 = 29493
Step 88: 29493 + 339 = 29832
Step 89: 29832 + 339 = 30171
Step 90: 30171 + 339 = 30510
Step 91: 30510 + 339 = 30849
Step 92: 30849 + 339 = 31188
Step 93: 31188 + 339 = 31527
Step 94: 31527 + 339 = 31866
Step 95: 31866 + 339 = 32205
Step 96: 32205 + 339 = 32544
Step 97: 32544 + 339 = 32883
Step 98: 32883 + 339 = 33222
Step 99: 33222 + 339 = 33561
Step 100: 33561 + 339 = 33900
Step 101: 33900 + 339 = 34239
Step 102: 34239 + 339 = 34578
Step 103: 34578 + 339 = 34917
Step 104: 34917 + 339 = 35256
Step 105: 35256 + 339 = 35595
Step 106: 35595 + 339 = 35934
Step 107: 35934 + 339 = 36273
Step 108: 36273 + 339 = 36612
Step 109: 36612 + 339 = 36951
Step 110: 36951 + 339 = 37290
Step 111: 37290 + 339 = 37629
Step 112: 37629 + 339 = 37968
Step 113: 37968 + 339 = 38307
Step 114: 38307 + 339 = 38646
Step 115: 38646 + 339 = 38985
Step 116: 38985 + 339 = 39324
Step 117: 39324 + 339 = 39663
Step 118: 39663 + 339 = 40002
Step 119: 40002 + 339 = 40341
Step 120: 40341 + 339 = 40680
Step 121: 40680 + 339 = 41019
Step 122: 41019 + 339 = 41358
Step 123: 41358 + 339 = 41697
Step 124: 41697 + 339 = 42036
Step 125: 42036 + 339 = 42375
Step 126: 42375 + 339 = 42714
Step 127: 42714 + 339 = 43053
Step 128: 43053 + 339 = 43392
Step 129: 43392 + 339 = 43731
Step 130: 43731 + 339 = 44070
Step 131: 44070 + 339 = 44409
Step 132: 44409 + 339 = 44748
Step 133: 44748 + 339 = 45087
Step 134: 45087 + 339 = 45426
Step 135: 45426 + 339 = 45765
Step 136: 45765 + 339 = 46104
Step 137: 46104 + 339 = 46443
Step 138: 46443 + 339 = 46782
Step 139: 46782 + 339 = 47121
Step 140: 47121 + 339 = 47460
Step 141: 47460 + 339 = 47799
Step 142: 47799 + 339 = 48138
Step 143: 48138 + 339 = 48477
Step 144: 48477 + 339 = 48816
Step 145: 48816 + 339 = 49155
Step 146: 49155 + 339 = 49494
Step 147: 49494 + 339 = 49833
Step 148: 49833 + 339 = 50172
Step 149: 50172 + 339 = 50511
Step 150: 50511 + 339 = 50850
Step 151: 50850 + 339 = 51189
Step 152: 51189 + 339 = 51528
Step 153: 51528 + 339 = 51867
Step 154: 51867 + 339 = 52206
Step 155: 52206 + 339 = 52545
Step 156: 52545 + 339 = 52884
Step 157: 52884 + 339 = 53223
Step 158: 53223 + 339 = 53562
Step 159: 53562 + 339 = 53901
Step 160: 53901 + 339 = 54240
Step 161: 54240 + 339 = 54579
Step 162: 54579 + 339 = 54918
Step 163: 54918 + 339 = 55257
Step 164: 55257 + 339 = 55596
Step 165: 55596 + 339 = 55935
Step 166: 55935 + 339 = 56274
Step 167: 56274 + 339 = 56613
Step 168: 56613 + 339 = 56952
Step 169: 56952 + 339 = 57291
Step 170: 57291 + 339 = 57630
Step 171: 57630 + 339 = 57969
Step 172: 57969 + 339 = 58308
Step 173: 58308 + 339 = 58647
Step 174: 58647 + 339 = 58986
Step 175: 58986 + 339 = 59325
Step 176: 59325 + 339 = 59664
Step 177: 59664 + 339 = 60003
Step 178: 60003 + 339 = 60342
Step 179: 60342 + 339 = 60681
Step 180: 60681 + 339 = 61020
Step 181: 61020 + 339 = 61359
Step 182: 61359 + 339 = 61698
Step 183: 61698 + 339 = 62037
Step 184: 62037 + 339 = 62376
Step 185: 62376 + 339 = 62715
Step 186: 62715 + 339 = 63054
Step 187: 63054 + 339 = 63393
Step 188: 63393 + 339 = 63732
Step 189: 63732 + 339 = 64071
Step 190: 64071 + 339 = 64410
Step 191: 64410 + 339 = 64749
Step 192: 64749 + 339 = 65088
Step 193: 65088 + 339 = 65427
Step 194: 65427 + 339 = 65766
Step 195: 65766 + 339 = 66105
Step 196: 66105 + 339 = 66444
Step 197: 66444 + 339 = 66783
Step 198: 66783 + 339 = 67122
Step 199: 67122 + 339 = 67461
Step 200: 67461 + 339 = 67800
Step 201: 67800 + 339 = 68139
Step 202: 68139 + 339 = 68478
Step 203: 68478 + 339 = 68817
Step 204: 68817 + 339 = 69156
Step 205: 69156 + 339 = 69495
Step 206: 69495 + 339 = 69834
Step 207: 69834 + 339 = 70173
Step 208: 70173 + 339 = 70512
Step 209: 70512 + 339 = 70851
Step 210: 70851 + 339 = 71190
Step 211: 71190 + 339 = 71529
Step 212: 71529 + 339 = 71868
Step 213: 71868 + 339 = 72207
Step 214: 72207 + 339 = 72546
Step 215: 72546 + 339 = 72885
Step 216: 72885 + 339 = 73224
Step 217: 73224 + 339 = 73563
Step 218: 73563 + 339 = 73902
Step 219: 73902 + 339 = 74241
Step 220: 74241 + 339 = 74580
Step 221: 74580 + 339 = 74919
Step 222: 74919 + 339 = 75258
Step 223: 75258 + 339 = 75597
Step 224: 75597 + 339 = 75936
Step 225: 75936 + 339 = 76275
Step 226: 76275 + 339 = 76614
Step 227: 76614 + 339 = 76953
Step 228: 76953 + 339 = 77292
Step 229: 77292 + 339 = 77631
Step 230: 77631 + 339 = 77970
Step 231: 77970 + 339 = 78309
Step 232: 78309 + 339 = 78648
Step 233: 78648 + 339 = 78987
Step 234: 78987 + 339 = 79326
Step 235: 79326 + 339 = 79665
Step 236: 79665 + 339 = 80004
Step 237: 80004 + 339 = 80343
Step 238: 80343 + 339 = 80682
Step 239: 80682 + 339 = 81021
Step 240: 81021 + 339 = 81360
Step 241: 81360 + 339 = 81699
Step 242: 81699 + 339 = 82038
Step 243: 82038 + 339 = 82377
Step 244: 82377 + 339 = 82716
Step 245: 82716 + 339 = 83055
Step 246: 83055 + 339 = 83394
Step 247: 83394 + 339 = 83733
Step 248: 83733 + 339 = 84072
Step 249: 84072 + 339 = 84411
Step 250: 84411 + 339 = 84750
Step 251: 84750 + 339 = 85089
Step 252: 85089 + 339 = 85428
Step 253: 85428 + 339 = 85767
Step 254: 85767 + 339 = 86106
Step 255: 86106 + 339 = 86445
Step 256: 86445 + 339 = 86784
Step 257: 86784 + 339 = 87123
Step 258: 87123 + 339 = 87462
Step 259: 87462 + 339 = 87801
Step 260: 87801 + 339 = 88140
Step 261: 88140 + 339 = 88479
Step 262: 88479 + 339 = 88818
Step 263: 88818 + 339 = 89157
Step 264: 89157 + 339 = 89496
Step 265: 89496 + 339 = 89835
Step 266: 89835 + 339 = 90174
Step 267: 90174 + 339 = 90513
Step 268: 90513 + 339 = 90852
Step 269: 90852 + 339 = 91191
Step 270: 91191 + 339 = 91530
Step 271: 91530 + 339 = 91869
Step 272: 91869 + 339 = 92208
Step 273: 92208 + 339 = 92547
Step 274: 92547 + 339 = 92886
Step 275: 92886 + 339 = 93225
Step 276: 93225 + 339 = 93564
Step 277: 93564 + 339 = 93903
Step 278: 93903 + 339 = 94242
Step 279: 94242 + 339 = 94581
Step 280: 94581 + 339 = 94920
Step 281: 94920 + 339 = 95259
Step 282: 95259 + 339 = 95598
Step 283: 95598 + 339 = 95937
Step 284: 95937 + 339 = 96276
Step 285: 96276 + 339 = 96615
Step 286: 96615 + 339 = 96954
Step 287: 96954 + 339 = 97293
Step 288: 97293 + 339 = 97632
Step 289: 97632 + 339 = 97971
Step 290: 97971 + 339 = 98310
Step 291: 98310 + 339 = 98649
Step 292: 98649 + 339 = 98988
Step 293: 98988 + 339 = 99327
Step 294: 99327 + 339 = 99666
Step 295: 99666 + 339 = 100005
Step 296: 100005 + 339 = 100344
Step 297: 100344 + 339 = 100683
Step 298: 100683 + 339 = 101022
Step 299: 101022 + 339 = 101361
Step 300: 101361 + 339 = 101700
Step 301: 101700 + 339 = 102039
Step 302: 102039 + 339 = 102378
Step 303: 102378 + 339 = 102717
Step 304: 102717 + 339 = 103056
Step 305: 103056 + 339 = 103395
Step 306: 103395 + 339 = 103734
Step 307: 103734 + 339 = 104073
Step 308: 104073 + 339 = 104412
Step 309: 104412 + 339 = 104751
Step 310: 104751 + 339 = 105090
Step 311: 105090 + 339 = 105429
Step 312: 105429 + 339 = 105768
Step 313: 105768 + 339 = 106107
Step 314: 106107 + 339 = 106446
Step 315: 106446 + 339 = 106785
Step 316: 106785 + 339 = 107124
Step 317: 107124 + 339 = 107463
Step 318: 107463 + 339 = 107802
Step 319: 107802 + 339 = 108141
Step 320: 108141 + 339 = 108480
Step 321: 108480 + 339 = 108819
Step 322: 108819 + 339 = 109158
Step 323: 109158 + 339 = 109497
Step 324: 109497 + 339 = 109836
Step 325: 109836 + 339 = 110175
Step 326: 110175 + 339 = 110514
Step 327: 110514 + 339 = 110853
Step 328: 110853 + 339 = 111192
Step 329: 111192 + 339 = 111531
Step 330: 111531 + 339 = 111870
Step 331: 111870 + 339 = 112209
Step 332: 112209 + 339 = 112548
Step 333: 112548 + 339 = 112887
Step 334: 112887 + 339 = 113226
Step 335: 113226 + 339 = 113565
Step 336: 113565 + 339 = 113904
Step 337: 113904 + 339 = 114243
Step 338: 114243 + 339 = 114582
Step 339: 114582 + 339 = 114921
Step 340: 114921 + 339 = 115260
Step 341: 115260 + 339 = 115599
Step 342: 115599 + 339 = 115938
Step 343: 115938 + 339 = 116277
Step 344: 116277 + 339 = 116616
Step 345: 116616 + 339 = 116955
Step 346: 116955 + 339 = 117294
Step 347: 117294 + 339 = 117633
Step 348: 117633 + 339 = 117972
Step 349: 117972 + 339 = 118311
Step 350: 118311 + 339 = 118650
Step 351: 118650 + 339 = 118989
Step 352: 118989 + 339 = 119328
Step 353: 119328 + 339 = 119667
Step 354: 119667 + 339 = 120006
Step 355: 120006 + 339 = 120345
Step 356: 120345 + 339 = 120684
Step 357: 120684 + 339 = 121023
Step 358: 121023 + 339 = 121362
Step 359: 121362 + 339 = 121701
Step 360: 121701 + 339 = 122040
Step 361: 122040 + 339 = 122379
Step 362: 122379 + 339 = 122718
Step 363: 122718 + 339 = 123057
Step 364: 123057 + 339 = 123396
Step 365: 123396 + 339 = 123735
Step 366: 123735 + 339 = 124074
Step 367: 124074 + 339 = 124413
Step 368: 124413 + 339 = 124752
Step 369: 124752 + 339 = 125091
Step 370: 125091 + 339 = 125430
Step 371: 125430 + 339 = 125769
Step 372: 125769 + 339 = 126108
Step 373: 126108 + 339 = 126447
Step 374: 126447 + 339 = 126786
Step 375: 126786 + 339 = 127125
Step 376: 127125 + 339 = 127464
Step 377: 127464 + 339 = 127803
Step 378: 127803 + 339 = 128142
Step 379: 128142 + 339 = 128481
Step 380: 128481 + 339 = 128820
Step 381: 128820 + 339 = 129159
Step 382: 129159 + 339 = 129498
Step 383: 129498 + 339 = 129837
Step 384: 129837 + 339 = 130176
Step 385: 130176 + 339 = 130515
Step 386: 130515 + 339 = 130854
Step 387: 130854 + 339 = 131193
Step 388: 131193 + 339 = 131532
Step 389: 131532 + 339 = 131871
Step 390: 131871 + 339 = 132210
Step 391: 132210 + 339 = 132549
Step 392: 132549 + 339 = 132888
Step 393: 132888 + 339 = 133227
Step 394: 133227 + 339 = 133566
Step 395: 133566 + 339 = 133905
Step 396: 133905 + 339 = 134244
Step 397: 134244 + 339 = 134583
Step 398: 134583 + 339 = 134922
Step 399: 134922 + 339 = 135261
Step 400: 135261 + 339 = 135600

So, 339*400 = 135600