Let's get this math done. We have 667 and we're going to multiply it by 5. This is the same as taking 667 and adding it to itself 5 times.
Step 1: 0 + 667 = 667
Step 2: 667 + 667 = 1334
Step 3: 1334 + 667 = 2001
Step 4: 2001 + 667 = 2668
Step 5: 2668 + 667 = 3335

So, 667*5 = 3335