OK, let's crack this. We're given 455 and our task is to multiply it by 4. Essentially, we'll be adding 455 to itself 4 times.
Step 1: 0 + 455 = 455
Step 2: 455 + 455 = 910
Step 3: 910 + 455 = 1365
Step 4: 1365 + 455 = 1820

So, 455*4 = 1820