Let's roll up our sleeves and solve this. We have 689 and we're going to multiply it by 25, essentially adding 689 to itself 25 times.
Step 1: 0 + 689 = 689
Step 2: 689 + 689 = 1378
Step 3: 1378 + 689 = 2067
Step 4: 2067 + 689 = 2756
Step 5: 2756 + 689 = 3445
Step 6: 3445 + 689 = 4134
Step 7: 4134 + 689 = 4823
Step 8: 4823 + 689 = 5512
Step 9: 5512 + 689 = 6201
Step 10: 6201 + 689 = 6890
Step 11: 6890 + 689 = 7579
Step 12: 7579 + 689 = 8268
Step 13: 8268 + 689 = 8957
Step 14: 8957 + 689 = 9646
Step 15: 9646 + 689 = 10335
Step 16: 10335 + 689 = 11024
Step 17: 11024 + 689 = 11713
Step 18: 11713 + 689 = 12402
Step 19: 12402 + 689 = 13091
Step 20: 13091 + 689 = 13780
Step 21: 13780 + 689 = 14469
Step 22: 14469 + 689 = 15158
Step 23: 15158 + 689 = 15847
Step 24: 15847 + 689 = 16536
Step 25: 16536 + 689 = 17225

So, 689*25 = 17225