Alright, let's solve this math problem step by step. First, we have the number 851. 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 851 and add it to itself 10 times.
Step 1: 0 + 851 = 851
Step 2: 851 + 851 = 1702
Step 3: 1702 + 851 = 2553
Step 4: 2553 + 851 = 3404
Step 5: 3404 + 851 = 4255
Step 6: 4255 + 851 = 5106
Step 7: 5106 + 851 = 5957
Step 8: 5957 + 851 = 6808
Step 9: 6808 + 851 = 7659
Step 10: 7659 + 851 = 8510

So, 851*10 = 8510