OK, let's crack this. We're given 671 and our task is to multiply it by 6. Essentially, we'll be adding 671 to itself 6 times.
Step 1: 0 + 671 = 671
Step 2: 671 + 671 = 1342
Step 3: 1342 + 671 = 2013
Step 4: 2013 + 671 = 2684
Step 5: 2684 + 671 = 3355
Step 6: 3355 + 671 = 4026

So, 671*6 = 4026