OK, let's crack this. We're given 545 and our task is to multiply it by 3. Essentially, we'll be adding 545 to itself 3 times.
Step 1: 0 + 545 = 545
Step 2: 545 + 545 = 1090
Step 3: 1090 + 545 = 1635

So, 545*3 = 1635