Alright, let's solve this math problem step by step. First, we have the number 686. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 25. So, we're going to take the number 686 and add it to itself 25 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
Step 24: 15778 + 686 = 16464
Step 25: 16464 + 686 = 17150

So, 686*25 = 17150