Let's roll up our sleeves and solve this. We have 555 and we're going to multiply it by 4, essentially adding 555 to itself 4 times.
Step 1: 0 + 555 = 555
Step 2: 555 + 555 = 1110
Step 3: 1110 + 555 = 1665
Step 4: 1665 + 555 = 2220

So, 555*4 = 2220