OK, let's work through this together. We're starting with 686 and we're going to multiply it by 23, which means we add 686 to itself 23 times.
Step 1: 0 + 686 = 686
Step 2: 686 + 686 = 1372
Step 3: 1372 + 686 = 2058
Step 4: 2058 + 686 = 2744
Step 5: 2744 + 686 = 3430
Step 6: 3430 + 686 = 4116
Step 7: 4116 + 686 = 4802
Step 8: 4802 + 686 = 5488
Step 9: 5488 + 686 = 6174
Step 10: 6174 + 686 = 6860
Step 11: 6860 + 686 = 7546
Step 12: 7546 + 686 = 8232
Step 13: 8232 + 686 = 8918
Step 14: 8918 + 686 = 9604
Step 15: 9604 + 686 = 10290
Step 16: 10290 + 686 = 10976
Step 17: 10976 + 686 = 11662
Step 18: 11662 + 686 = 12348
Step 19: 12348 + 686 = 13034
Step 20: 13034 + 686 = 13720
Step 21: 13720 + 686 = 14406
Step 22: 14406 + 686 = 15092
Step 23: 15092 + 686 = 15778

So, 686*23 = 15778