OK, let's work through this together. We're starting with 256 and we're going to multiply it by 139, which means we add 256 to itself 139 times.
Step 1: 0 + 256 = 256
Step 2: 256 + 256 = 512
Step 3: 512 + 256 = 768
Step 4: 768 + 256 = 1024
Step 5: 1024 + 256 = 1280
Step 6: 1280 + 256 = 1536
Step 7: 1536 + 256 = 1792
Step 8: 1792 + 256 = 2048
Step 9: 2048 + 256 = 2304
Step 10: 2304 + 256 = 2560
Step 11: 2560 + 256 = 2816
Step 12: 2816 + 256 = 3072
Step 13: 3072 + 256 = 3328
Step 14: 3328 + 256 = 3584
Step 15: 3584 + 256 = 3840
Step 16: 3840 + 256 = 4096
Step 17: 4096 + 256 = 4352
Step 18: 4352 + 256 = 4608
Step 19: 4608 + 256 = 4864
Step 20: 4864 + 256 = 5120
Step 21: 5120 + 256 = 5376
Step 22: 5376 + 256 = 5632
Step 23: 5632 + 256 = 5888
Step 24: 5888 + 256 = 6144
Step 25: 6144 + 256 = 6400
Step 26: 6400 + 256 = 6656
Step 27: 6656 + 256 = 6912
Step 28: 6912 + 256 = 7168
Step 29: 7168 + 256 = 7424
Step 30: 7424 + 256 = 7680
Step 31: 7680 + 256 = 7936
Step 32: 7936 + 256 = 8192
Step 33: 8192 + 256 = 8448
Step 34: 8448 + 256 = 8704
Step 35: 8704 + 256 = 8960
Step 36: 8960 + 256 = 9216
Step 37: 9216 + 256 = 9472
Step 38: 9472 + 256 = 9728
Step 39: 9728 + 256 = 9984
Step 40: 9984 + 256 = 10240
Step 41: 10240 + 256 = 10496
Step 42: 10496 + 256 = 10752
Step 43: 10752 + 256 = 11008
Step 44: 11008 + 256 = 11264
Step 45: 11264 + 256 = 11520
Step 46: 11520 + 256 = 11776
Step 47: 11776 + 256 = 12032
Step 48: 12032 + 256 = 12288
Step 49: 12288 + 256 = 12544
Step 50: 12544 + 256 = 12800
Step 51: 12800 + 256 = 13056
Step 52: 13056 + 256 = 13312
Step 53: 13312 + 256 = 13568
Step 54: 13568 + 256 = 13824
Step 55: 13824 + 256 = 14080
Step 56: 14080 + 256 = 14336
Step 57: 14336 + 256 = 14592
Step 58: 14592 + 256 = 14848
Step 59: 14848 + 256 = 15104
Step 60: 15104 + 256 = 15360
Step 61: 15360 + 256 = 15616
Step 62: 15616 + 256 = 15872
Step 63: 15872 + 256 = 16128
Step 64: 16128 + 256 = 16384
Step 65: 16384 + 256 = 16640
Step 66: 16640 + 256 = 16896
Step 67: 16896 + 256 = 17152
Step 68: 17152 + 256 = 17408
Step 69: 17408 + 256 = 17664
Step 70: 17664 + 256 = 17920
Step 71: 17920 + 256 = 18176
Step 72: 18176 + 256 = 18432
Step 73: 18432 + 256 = 18688
Step 74: 18688 + 256 = 18944
Step 75: 18944 + 256 = 19200
Step 76: 19200 + 256 = 19456
Step 77: 19456 + 256 = 19712
Step 78: 19712 + 256 = 19968
Step 79: 19968 + 256 = 20224
Step 80: 20224 + 256 = 20480
Step 81: 20480 + 256 = 20736
Step 82: 20736 + 256 = 20992
Step 83: 20992 + 256 = 21248
Step 84: 21248 + 256 = 21504
Step 85: 21504 + 256 = 21760
Step 86: 21760 + 256 = 22016
Step 87: 22016 + 256 = 22272
Step 88: 22272 + 256 = 22528
Step 89: 22528 + 256 = 22784
Step 90: 22784 + 256 = 23040
Step 91: 23040 + 256 = 23296
Step 92: 23296 + 256 = 23552
Step 93: 23552 + 256 = 23808
Step 94: 23808 + 256 = 24064
Step 95: 24064 + 256 = 24320
Step 96: 24320 + 256 = 24576
Step 97: 24576 + 256 = 24832
Step 98: 24832 + 256 = 25088
Step 99: 25088 + 256 = 25344
Step 100: 25344 + 256 = 25600
Step 101: 25600 + 256 = 25856
Step 102: 25856 + 256 = 26112
Step 103: 26112 + 256 = 26368
Step 104: 26368 + 256 = 26624
Step 105: 26624 + 256 = 26880
Step 106: 26880 + 256 = 27136
Step 107: 27136 + 256 = 27392
Step 108: 27392 + 256 = 27648
Step 109: 27648 + 256 = 27904
Step 110: 27904 + 256 = 28160
Step 111: 28160 + 256 = 28416
Step 112: 28416 + 256 = 28672
Step 113: 28672 + 256 = 28928
Step 114: 28928 + 256 = 29184
Step 115: 29184 + 256 = 29440
Step 116: 29440 + 256 = 29696
Step 117: 29696 + 256 = 29952
Step 118: 29952 + 256 = 30208
Step 119: 30208 + 256 = 30464
Step 120: 30464 + 256 = 30720
Step 121: 30720 + 256 = 30976
Step 122: 30976 + 256 = 31232
Step 123: 31232 + 256 = 31488
Step 124: 31488 + 256 = 31744
Step 125: 31744 + 256 = 32000
Step 126: 32000 + 256 = 32256
Step 127: 32256 + 256 = 32512
Step 128: 32512 + 256 = 32768
Step 129: 32768 + 256 = 33024
Step 130: 33024 + 256 = 33280
Step 131: 33280 + 256 = 33536
Step 132: 33536 + 256 = 33792
Step 133: 33792 + 256 = 34048
Step 134: 34048 + 256 = 34304
Step 135: 34304 + 256 = 34560
Step 136: 34560 + 256 = 34816
Step 137: 34816 + 256 = 35072
Step 138: 35072 + 256 = 35328
Step 139: 35328 + 256 = 35584

So, 256*139 = 35584