Sure thing, let's get straight to it. We start with 678 and we're going to multiply it by 5, which means adding 678 to itself 5 times.
Step 1: 0 + 678 = 678
Step 2: 678 + 678 = 1356
Step 3: 1356 + 678 = 2034
Step 4: 2034 + 678 = 2712
Step 5: 2712 + 678 = 3390

So, 678*5 = 3390