OK, let's crack this. We're given 108 and our task is to multiply it by 5. Essentially, we'll be adding 108 to itself 5 times.
Step 1: 0 + 108 = 108
Step 2: 108 + 108 = 216
Step 3: 216 + 108 = 324
Step 4: 324 + 108 = 432
Step 5: 432 + 108 = 540

So, 108*5 = 540