OK, let's work through this together. We're starting with 255 and we're going to multiply it by 17, which means we add 255 to itself 17 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

So, 255*17 = 4335