Sure thing, let's get straight to it. We start with 135 and we're going to multiply it by 4, which means adding 135 to itself 4 times.
Step 1: 0 + 135 = 135
Step 2: 135 + 135 = 270
Step 3: 270 + 135 = 405
Step 4: 405 + 135 = 540

So, 135*4 = 540