Alright, let's solve this math problem step by step. First, we have the number 421. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 12. So, we're going to take the number 421 and add it to itself 12 times.
Step 1: 0 + 421 = 421
Step 2: 421 + 421 = 842
Step 3: 842 + 421 = 1263
Step 4: 1263 + 421 = 1684
Step 5: 1684 + 421 = 2105
Step 6: 2105 + 421 = 2526
Step 7: 2526 + 421 = 2947
Step 8: 2947 + 421 = 3368
Step 9: 3368 + 421 = 3789
Step 10: 3789 + 421 = 4210
Step 11: 4210 + 421 = 4631
Step 12: 4631 + 421 = 5052

So, 421*12 = 5052