Let's roll up our sleeves and solve this. We have 689 and we're going to multiply it by 45, essentially adding 689 to itself 45 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
Step 26: 17225 + 689 = 17914
Step 27: 17914 + 689 = 18603
Step 28: 18603 + 689 = 19292
Step 29: 19292 + 689 = 19981
Step 30: 19981 + 689 = 20670
Step 31: 20670 + 689 = 21359
Step 32: 21359 + 689 = 22048
Step 33: 22048 + 689 = 22737
Step 34: 22737 + 689 = 23426
Step 35: 23426 + 689 = 24115
Step 36: 24115 + 689 = 24804
Step 37: 24804 + 689 = 25493
Step 38: 25493 + 689 = 26182
Step 39: 26182 + 689 = 26871
Step 40: 26871 + 689 = 27560
Step 41: 27560 + 689 = 28249
Step 42: 28249 + 689 = 28938
Step 43: 28938 + 689 = 29627
Step 44: 29627 + 689 = 30316
Step 45: 30316 + 689 = 31005

So, 689*45 = 31005