OK, let's crack this. We're given 255 and our task is to multiply it by 63. Essentially, we'll be adding 255 to itself 63 times.
Step 1: 0 + 255 = 255
Step 2: 255 + 255 = 510
Step 3: 510 + 255 = 765
Step 4: 765 + 255 = 1020
Step 5: 1020 + 255 = 1275
Step 6: 1275 + 255 = 1530
Step 7: 1530 + 255 = 1785
Step 8: 1785 + 255 = 2040
Step 9: 2040 + 255 = 2295
Step 10: 2295 + 255 = 2550
Step 11: 2550 + 255 = 2805
Step 12: 2805 + 255 = 3060
Step 13: 3060 + 255 = 3315
Step 14: 3315 + 255 = 3570
Step 15: 3570 + 255 = 3825
Step 16: 3825 + 255 = 4080
Step 17: 4080 + 255 = 4335
Step 18: 4335 + 255 = 4590
Step 19: 4590 + 255 = 4845
Step 20: 4845 + 255 = 5100
Step 21: 5100 + 255 = 5355
Step 22: 5355 + 255 = 5610
Step 23: 5610 + 255 = 5865
Step 24: 5865 + 255 = 6120
Step 25: 6120 + 255 = 6375
Step 26: 6375 + 255 = 6630
Step 27: 6630 + 255 = 6885
Step 28: 6885 + 255 = 7140
Step 29: 7140 + 255 = 7395
Step 30: 7395 + 255 = 7650
Step 31: 7650 + 255 = 7905
Step 32: 7905 + 255 = 8160
Step 33: 8160 + 255 = 8415
Step 34: 8415 + 255 = 8670
Step 35: 8670 + 255 = 8925
Step 36: 8925 + 255 = 9180
Step 37: 9180 + 255 = 9435
Step 38: 9435 + 255 = 9690
Step 39: 9690 + 255 = 9945
Step 40: 9945 + 255 = 10200
Step 41: 10200 + 255 = 10455
Step 42: 10455 + 255 = 10710
Step 43: 10710 + 255 = 10965
Step 44: 10965 + 255 = 11220
Step 45: 11220 + 255 = 11475
Step 46: 11475 + 255 = 11730
Step 47: 11730 + 255 = 11985
Step 48: 11985 + 255 = 12240
Step 49: 12240 + 255 = 12495
Step 50: 12495 + 255 = 12750
Step 51: 12750 + 255 = 13005
Step 52: 13005 + 255 = 13260
Step 53: 13260 + 255 = 13515
Step 54: 13515 + 255 = 13770
Step 55: 13770 + 255 = 14025
Step 56: 14025 + 255 = 14280
Step 57: 14280 + 255 = 14535
Step 58: 14535 + 255 = 14790
Step 59: 14790 + 255 = 15045
Step 60: 15045 + 255 = 15300
Step 61: 15300 + 255 = 15555
Step 62: 15555 + 255 = 15810
Step 63: 15810 + 255 = 16065

So, 255*63 = 16065