OK, let's crack this. We're given 51 and our task is to multiply it by 5. Essentially, we'll be adding 51 to itself 5 times.
Step 1: 0 + 51 = 51
Step 2: 51 + 51 = 102
Step 3: 102 + 51 = 153
Step 4: 153 + 51 = 204
Step 5: 204 + 51 = 255

So, 51*5 = 255