Alright, let's solve this math problem step by step. First, we have the number 813. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 16. So, we're going to take the number 813 and add it to itself 16 times.
Step 1: 0 + 813 = 813
Step 2: 813 + 813 = 1626
Step 3: 1626 + 813 = 2439
Step 4: 2439 + 813 = 3252
Step 5: 3252 + 813 = 4065
Step 6: 4065 + 813 = 4878
Step 7: 4878 + 813 = 5691
Step 8: 5691 + 813 = 6504
Step 9: 6504 + 813 = 7317
Step 10: 7317 + 813 = 8130
Step 11: 8130 + 813 = 8943
Step 12: 8943 + 813 = 9756
Step 13: 9756 + 813 = 10569
Step 14: 10569 + 813 = 11382
Step 15: 11382 + 813 = 12195
Step 16: 12195 + 813 = 13008

So, 813*16 = 13008