Alright, let's solve this math problem step by step. First, we have the number 610. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 21. So, we're going to take the number 610 and add it to itself 21 times.
Step 1: 0 + 610 = 610
Step 2: 610 + 610 = 1220
Step 3: 1220 + 610 = 1830
Step 4: 1830 + 610 = 2440
Step 5: 2440 + 610 = 3050
Step 6: 3050 + 610 = 3660
Step 7: 3660 + 610 = 4270
Step 8: 4270 + 610 = 4880
Step 9: 4880 + 610 = 5490
Step 10: 5490 + 610 = 6100
Step 11: 6100 + 610 = 6710
Step 12: 6710 + 610 = 7320
Step 13: 7320 + 610 = 7930
Step 14: 7930 + 610 = 8540
Step 15: 8540 + 610 = 9150
Step 16: 9150 + 610 = 9760
Step 17: 9760 + 610 = 10370
Step 18: 10370 + 610 = 10980
Step 19: 10980 + 610 = 11590
Step 20: 11590 + 610 = 12200
Step 21: 12200 + 610 = 12810

So, 610*21 = 12810