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 9. So, we're going to take the number 813 and add it to itself 9 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

So, 813*9 = 7317