Alright, let's solve this math problem step by step. First, we have the number 665. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 5. So, we're going to take the number 665 and add it to itself 5 times.
Step 1: 0 + 665 = 665
Step 2: 665 + 665 = 1330
Step 3: 1330 + 665 = 1995
Step 4: 1995 + 665 = 2660
Step 5: 2660 + 665 = 3325

So, 665*5 = 3325