Let's roll up our sleeves and solve this. We have 933 and we're going to multiply it by 13, essentially adding 933 to itself 13 times.
Step 1: 0 + 933 = 933
Step 2: 933 + 933 = 1866
Step 3: 1866 + 933 = 2799
Step 4: 2799 + 933 = 3732
Step 5: 3732 + 933 = 4665
Step 6: 4665 + 933 = 5598
Step 7: 5598 + 933 = 6531
Step 8: 6531 + 933 = 7464
Step 9: 7464 + 933 = 8397
Step 10: 8397 + 933 = 9330
Step 11: 9330 + 933 = 10263
Step 12: 10263 + 933 = 11196
Step 13: 11196 + 933 = 12129

So, 933*13 = 12129