Alright, let's solve this math problem step by step. First, we have the number 669. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 91. So, we're going to take the number 669 and add it to itself 91 times.
Step 1: 0 + 669 = 669
Step 2: 669 + 669 = 1338
Step 3: 1338 + 669 = 2007
Step 4: 2007 + 669 = 2676
Step 5: 2676 + 669 = 3345
Step 6: 3345 + 669 = 4014
Step 7: 4014 + 669 = 4683
Step 8: 4683 + 669 = 5352
Step 9: 5352 + 669 = 6021
Step 10: 6021 + 669 = 6690
Step 11: 6690 + 669 = 7359
Step 12: 7359 + 669 = 8028
Step 13: 8028 + 669 = 8697
Step 14: 8697 + 669 = 9366
Step 15: 9366 + 669 = 10035
Step 16: 10035 + 669 = 10704
Step 17: 10704 + 669 = 11373
Step 18: 11373 + 669 = 12042
Step 19: 12042 + 669 = 12711
Step 20: 12711 + 669 = 13380
Step 21: 13380 + 669 = 14049
Step 22: 14049 + 669 = 14718
Step 23: 14718 + 669 = 15387
Step 24: 15387 + 669 = 16056
Step 25: 16056 + 669 = 16725
Step 26: 16725 + 669 = 17394
Step 27: 17394 + 669 = 18063
Step 28: 18063 + 669 = 18732
Step 29: 18732 + 669 = 19401
Step 30: 19401 + 669 = 20070
Step 31: 20070 + 669 = 20739
Step 32: 20739 + 669 = 21408
Step 33: 21408 + 669 = 22077
Step 34: 22077 + 669 = 22746
Step 35: 22746 + 669 = 23415
Step 36: 23415 + 669 = 24084
Step 37: 24084 + 669 = 24753
Step 38: 24753 + 669 = 25422
Step 39: 25422 + 669 = 26091
Step 40: 26091 + 669 = 26760
Step 41: 26760 + 669 = 27429
Step 42: 27429 + 669 = 28098
Step 43: 28098 + 669 = 28767
Step 44: 28767 + 669 = 29436
Step 45: 29436 + 669 = 30105
Step 46: 30105 + 669 = 30774
Step 47: 30774 + 669 = 31443
Step 48: 31443 + 669 = 32112
Step 49: 32112 + 669 = 32781
Step 50: 32781 + 669 = 33450
Step 51: 33450 + 669 = 34119
Step 52: 34119 + 669 = 34788
Step 53: 34788 + 669 = 35457
Step 54: 35457 + 669 = 36126
Step 55: 36126 + 669 = 36795
Step 56: 36795 + 669 = 37464
Step 57: 37464 + 669 = 38133
Step 58: 38133 + 669 = 38802
Step 59: 38802 + 669 = 39471
Step 60: 39471 + 669 = 40140
Step 61: 40140 + 669 = 40809
Step 62: 40809 + 669 = 41478
Step 63: 41478 + 669 = 42147
Step 64: 42147 + 669 = 42816
Step 65: 42816 + 669 = 43485
Step 66: 43485 + 669 = 44154
Step 67: 44154 + 669 = 44823
Step 68: 44823 + 669 = 45492
Step 69: 45492 + 669 = 46161
Step 70: 46161 + 669 = 46830
Step 71: 46830 + 669 = 47499
Step 72: 47499 + 669 = 48168
Step 73: 48168 + 669 = 48837
Step 74: 48837 + 669 = 49506
Step 75: 49506 + 669 = 50175
Step 76: 50175 + 669 = 50844
Step 77: 50844 + 669 = 51513
Step 78: 51513 + 669 = 52182
Step 79: 52182 + 669 = 52851
Step 80: 52851 + 669 = 53520
Step 81: 53520 + 669 = 54189
Step 82: 54189 + 669 = 54858
Step 83: 54858 + 669 = 55527
Step 84: 55527 + 669 = 56196
Step 85: 56196 + 669 = 56865
Step 86: 56865 + 669 = 57534
Step 87: 57534 + 669 = 58203
Step 88: 58203 + 669 = 58872
Step 89: 58872 + 669 = 59541
Step 90: 59541 + 669 = 60210
Step 91: 60210 + 669 = 60879

So, 669*91 = 60879