Alright, let's solve this math problem step by step. First, we have the number 503. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 10. So, we're going to take the number 503 and add it to itself 10 times.
Step 1: 0 + 503 = 503
Step 2: 503 + 503 = 1006
Step 3: 1006 + 503 = 1509
Step 4: 1509 + 503 = 2012
Step 5: 2012 + 503 = 2515
Step 6: 2515 + 503 = 3018
Step 7: 3018 + 503 = 3521
Step 8: 3521 + 503 = 4024
Step 9: 4024 + 503 = 4527
Step 10: 4527 + 503 = 5030

So, 503*10 = 5030