OK, let's crack this. We're given 793 and our task is to multiply it by 13. Essentially, we'll be adding 793 to itself 13 times.
Step 1: 0 + 793 = 793
Step 2: 793 + 793 = 1586
Step 3: 1586 + 793 = 2379
Step 4: 2379 + 793 = 3172
Step 5: 3172 + 793 = 3965
Step 6: 3965 + 793 = 4758
Step 7: 4758 + 793 = 5551
Step 8: 5551 + 793 = 6344
Step 9: 6344 + 793 = 7137
Step 10: 7137 + 793 = 7930
Step 11: 7930 + 793 = 8723
Step 12: 8723 + 793 = 9516
Step 13: 9516 + 793 = 10309

So, 793*13 = 10309