Alright, let's solve this math problem step by step. First, we have the number 255. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 15. So, we're going to take the number 255 and add it to itself 15 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

So, 255*15 = 3825