Let's roll up our sleeves and solve this. We have 855 and we're going to multiply it by 6, essentially adding 855 to itself 6 times.
Step 1: 0 + 855 = 855
Step 2: 855 + 855 = 1710
Step 3: 1710 + 855 = 2565
Step 4: 2565 + 855 = 3420
Step 5: 3420 + 855 = 4275
Step 6: 4275 + 855 = 5130

So, 855*6 = 5130