OK, let's work through this together. We're starting with 78 and we're going to multiply it by 11, which means we add 78 to itself 11 times.
Step 1: 0 + 78 = 78
Step 2: 78 + 78 = 156
Step 3: 156 + 78 = 234
Step 4: 234 + 78 = 312
Step 5: 312 + 78 = 390
Step 6: 390 + 78 = 468
Step 7: 468 + 78 = 546
Step 8: 546 + 78 = 624
Step 9: 624 + 78 = 702
Step 10: 702 + 78 = 780
Step 11: 780 + 78 = 858

So, 78*11 = 858