OK, let's crack this. We're given 661 and our task is to multiply it by 5. Essentially, we'll be adding 661 to itself 5 times.
Step 1: 0 + 661 = 661
Step 2: 661 + 661 = 1322
Step 3: 1322 + 661 = 1983
Step 4: 1983 + 661 = 2644
Step 5: 2644 + 661 = 3305

So, 661*5 = 3305