Alright, let's solve this math problem step by step. First, we have the number 646. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 2. So, we're going to take the number 646 and add it to itself 2 times.
Step 1: 0 + 646 = 646
Step 2: 646 + 646 = 1292

So, 646*2 = 1292