Let's roll up our sleeves and solve this. We have 64 and we're going to multiply it by 138, essentially adding 64 to itself 138 times.
Step 1: 0 + 64 = 64
Step 2: 64 + 64 = 128
Step 3: 128 + 64 = 192
Step 4: 192 + 64 = 256
Step 5: 256 + 64 = 320
Step 6: 320 + 64 = 384
Step 7: 384 + 64 = 448
Step 8: 448 + 64 = 512
Step 9: 512 + 64 = 576
Step 10: 576 + 64 = 640
Step 11: 640 + 64 = 704
Step 12: 704 + 64 = 768
Step 13: 768 + 64 = 832
Step 14: 832 + 64 = 896
Step 15: 896 + 64 = 960
Step 16: 960 + 64 = 1024
Step 17: 1024 + 64 = 1088
Step 18: 1088 + 64 = 1152
Step 19: 1152 + 64 = 1216
Step 20: 1216 + 64 = 1280
Step 21: 1280 + 64 = 1344
Step 22: 1344 + 64 = 1408
Step 23: 1408 + 64 = 1472
Step 24: 1472 + 64 = 1536
Step 25: 1536 + 64 = 1600
Step 26: 1600 + 64 = 1664
Step 27: 1664 + 64 = 1728
Step 28: 1728 + 64 = 1792
Step 29: 1792 + 64 = 1856
Step 30: 1856 + 64 = 1920
Step 31: 1920 + 64 = 1984
Step 32: 1984 + 64 = 2048
Step 33: 2048 + 64 = 2112
Step 34: 2112 + 64 = 2176
Step 35: 2176 + 64 = 2240
Step 36: 2240 + 64 = 2304
Step 37: 2304 + 64 = 2368
Step 38: 2368 + 64 = 2432
Step 39: 2432 + 64 = 2496
Step 40: 2496 + 64 = 2560
Step 41: 2560 + 64 = 2624
Step 42: 2624 + 64 = 2688
Step 43: 2688 + 64 = 2752
Step 44: 2752 + 64 = 2816
Step 45: 2816 + 64 = 2880
Step 46: 2880 + 64 = 2944
Step 47: 2944 + 64 = 3008
Step 48: 3008 + 64 = 3072
Step 49: 3072 + 64 = 3136
Step 50: 3136 + 64 = 3200
Step 51: 3200 + 64 = 3264
Step 52: 3264 + 64 = 3328
Step 53: 3328 + 64 = 3392
Step 54: 3392 + 64 = 3456
Step 55: 3456 + 64 = 3520
Step 56: 3520 + 64 = 3584
Step 57: 3584 + 64 = 3648
Step 58: 3648 + 64 = 3712
Step 59: 3712 + 64 = 3776
Step 60: 3776 + 64 = 3840
Step 61: 3840 + 64 = 3904
Step 62: 3904 + 64 = 3968
Step 63: 3968 + 64 = 4032
Step 64: 4032 + 64 = 4096
Step 65: 4096 + 64 = 4160
Step 66: 4160 + 64 = 4224
Step 67: 4224 + 64 = 4288
Step 68: 4288 + 64 = 4352
Step 69: 4352 + 64 = 4416
Step 70: 4416 + 64 = 4480
Step 71: 4480 + 64 = 4544
Step 72: 4544 + 64 = 4608
Step 73: 4608 + 64 = 4672
Step 74: 4672 + 64 = 4736
Step 75: 4736 + 64 = 4800
Step 76: 4800 + 64 = 4864
Step 77: 4864 + 64 = 4928
Step 78: 4928 + 64 = 4992
Step 79: 4992 + 64 = 5056
Step 80: 5056 + 64 = 5120
Step 81: 5120 + 64 = 5184
Step 82: 5184 + 64 = 5248
Step 83: 5248 + 64 = 5312
Step 84: 5312 + 64 = 5376
Step 85: 5376 + 64 = 5440
Step 86: 5440 + 64 = 5504
Step 87: 5504 + 64 = 5568
Step 88: 5568 + 64 = 5632
Step 89: 5632 + 64 = 5696
Step 90: 5696 + 64 = 5760
Step 91: 5760 + 64 = 5824
Step 92: 5824 + 64 = 5888
Step 93: 5888 + 64 = 5952
Step 94: 5952 + 64 = 6016
Step 95: 6016 + 64 = 6080
Step 96: 6080 + 64 = 6144
Step 97: 6144 + 64 = 6208
Step 98: 6208 + 64 = 6272
Step 99: 6272 + 64 = 6336
Step 100: 6336 + 64 = 6400
Step 101: 6400 + 64 = 6464
Step 102: 6464 + 64 = 6528
Step 103: 6528 + 64 = 6592
Step 104: 6592 + 64 = 6656
Step 105: 6656 + 64 = 6720
Step 106: 6720 + 64 = 6784
Step 107: 6784 + 64 = 6848
Step 108: 6848 + 64 = 6912
Step 109: 6912 + 64 = 6976
Step 110: 6976 + 64 = 7040
Step 111: 7040 + 64 = 7104
Step 112: 7104 + 64 = 7168
Step 113: 7168 + 64 = 7232
Step 114: 7232 + 64 = 7296
Step 115: 7296 + 64 = 7360
Step 116: 7360 + 64 = 7424
Step 117: 7424 + 64 = 7488
Step 118: 7488 + 64 = 7552
Step 119: 7552 + 64 = 7616
Step 120: 7616 + 64 = 7680
Step 121: 7680 + 64 = 7744
Step 122: 7744 + 64 = 7808
Step 123: 7808 + 64 = 7872
Step 124: 7872 + 64 = 7936
Step 125: 7936 + 64 = 8000
Step 126: 8000 + 64 = 8064
Step 127: 8064 + 64 = 8128
Step 128: 8128 + 64 = 8192
Step 129: 8192 + 64 = 8256
Step 130: 8256 + 64 = 8320
Step 131: 8320 + 64 = 8384
Step 132: 8384 + 64 = 8448
Step 133: 8448 + 64 = 8512
Step 134: 8512 + 64 = 8576
Step 135: 8576 + 64 = 8640
Step 136: 8640 + 64 = 8704
Step 137: 8704 + 64 = 8768
Step 138: 8768 + 64 = 8832

So, 64*138 = 8832