Without delay, let's solve this. We've got 768 and we will be multiplying it by 51, that is, adding 768 to itself 51 times.
Step 1: 0 + 768 = 768
Step 2: 768 + 768 = 1536
Step 3: 1536 + 768 = 2304
Step 4: 2304 + 768 = 3072
Step 5: 3072 + 768 = 3840
Step 6: 3840 + 768 = 4608
Step 7: 4608 + 768 = 5376
Step 8: 5376 + 768 = 6144
Step 9: 6144 + 768 = 6912
Step 10: 6912 + 768 = 7680
Step 11: 7680 + 768 = 8448
Step 12: 8448 + 768 = 9216
Step 13: 9216 + 768 = 9984
Step 14: 9984 + 768 = 10752
Step 15: 10752 + 768 = 11520
Step 16: 11520 + 768 = 12288
Step 17: 12288 + 768 = 13056
Step 18: 13056 + 768 = 13824
Step 19: 13824 + 768 = 14592
Step 20: 14592 + 768 = 15360
Step 21: 15360 + 768 = 16128
Step 22: 16128 + 768 = 16896
Step 23: 16896 + 768 = 17664
Step 24: 17664 + 768 = 18432
Step 25: 18432 + 768 = 19200
Step 26: 19200 + 768 = 19968
Step 27: 19968 + 768 = 20736
Step 28: 20736 + 768 = 21504
Step 29: 21504 + 768 = 22272
Step 30: 22272 + 768 = 23040
Step 31: 23040 + 768 = 23808
Step 32: 23808 + 768 = 24576
Step 33: 24576 + 768 = 25344
Step 34: 25344 + 768 = 26112
Step 35: 26112 + 768 = 26880
Step 36: 26880 + 768 = 27648
Step 37: 27648 + 768 = 28416
Step 38: 28416 + 768 = 29184
Step 39: 29184 + 768 = 29952
Step 40: 29952 + 768 = 30720
Step 41: 30720 + 768 = 31488
Step 42: 31488 + 768 = 32256
Step 43: 32256 + 768 = 33024
Step 44: 33024 + 768 = 33792
Step 45: 33792 + 768 = 34560
Step 46: 34560 + 768 = 35328
Step 47: 35328 + 768 = 36096
Step 48: 36096 + 768 = 36864
Step 49: 36864 + 768 = 37632
Step 50: 37632 + 768 = 38400
Step 51: 38400 + 768 = 39168

So, 768*51 = 39168