Sure thing, let's get straight to it. We start with 678 and we're going to multiply it by 19, which means adding 678 to itself 19 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
Step 6: 3390 + 678 = 4068
Step 7: 4068 + 678 = 4746
Step 8: 4746 + 678 = 5424
Step 9: 5424 + 678 = 6102
Step 10: 6102 + 678 = 6780
Step 11: 6780 + 678 = 7458
Step 12: 7458 + 678 = 8136
Step 13: 8136 + 678 = 8814
Step 14: 8814 + 678 = 9492
Step 15: 9492 + 678 = 10170
Step 16: 10170 + 678 = 10848
Step 17: 10848 + 678 = 11526
Step 18: 11526 + 678 = 12204
Step 19: 12204 + 678 = 12882

So, 678*19 = 12882