OK, let's crack this. We're given 678 and our task is to multiply it by 3. Essentially, we'll be adding 678 to itself 3 times.
Step 1: 0 + 678 = 678
Step 2: 678 + 678 = 1356
Step 3: 1356 + 678 = 2034

So, 678*3 = 2034