Alright, let's solve this math problem step by step. First, we have the number 621. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 4. So, we're going to take the number 621 and add it to itself 4 times.
Step 1: 0 + 621 = 621
Step 2: 621 + 621 = 1242
Step 3: 1242 + 621 = 1863
Step 4: 1863 + 621 = 2484

So, 621*4 = 2484