Sure thing, let's get straight to it. We start with 169 and we're going to multiply it by 91, which means adding 169 to itself 91 times.
Step 1: 0 + 169 = 169
Step 2: 169 + 169 = 338
Step 3: 338 + 169 = 507
Step 4: 507 + 169 = 676
Step 5: 676 + 169 = 845
Step 6: 845 + 169 = 1014
Step 7: 1014 + 169 = 1183
Step 8: 1183 + 169 = 1352
Step 9: 1352 + 169 = 1521
Step 10: 1521 + 169 = 1690
Step 11: 1690 + 169 = 1859
Step 12: 1859 + 169 = 2028
Step 13: 2028 + 169 = 2197
Step 14: 2197 + 169 = 2366
Step 15: 2366 + 169 = 2535
Step 16: 2535 + 169 = 2704
Step 17: 2704 + 169 = 2873
Step 18: 2873 + 169 = 3042
Step 19: 3042 + 169 = 3211
Step 20: 3211 + 169 = 3380
Step 21: 3380 + 169 = 3549
Step 22: 3549 + 169 = 3718
Step 23: 3718 + 169 = 3887
Step 24: 3887 + 169 = 4056
Step 25: 4056 + 169 = 4225
Step 26: 4225 + 169 = 4394
Step 27: 4394 + 169 = 4563
Step 28: 4563 + 169 = 4732
Step 29: 4732 + 169 = 4901
Step 30: 4901 + 169 = 5070
Step 31: 5070 + 169 = 5239
Step 32: 5239 + 169 = 5408
Step 33: 5408 + 169 = 5577
Step 34: 5577 + 169 = 5746
Step 35: 5746 + 169 = 5915
Step 36: 5915 + 169 = 6084
Step 37: 6084 + 169 = 6253
Step 38: 6253 + 169 = 6422
Step 39: 6422 + 169 = 6591
Step 40: 6591 + 169 = 6760
Step 41: 6760 + 169 = 6929
Step 42: 6929 + 169 = 7098
Step 43: 7098 + 169 = 7267
Step 44: 7267 + 169 = 7436
Step 45: 7436 + 169 = 7605
Step 46: 7605 + 169 = 7774
Step 47: 7774 + 169 = 7943
Step 48: 7943 + 169 = 8112
Step 49: 8112 + 169 = 8281
Step 50: 8281 + 169 = 8450
Step 51: 8450 + 169 = 8619
Step 52: 8619 + 169 = 8788
Step 53: 8788 + 169 = 8957
Step 54: 8957 + 169 = 9126
Step 55: 9126 + 169 = 9295
Step 56: 9295 + 169 = 9464
Step 57: 9464 + 169 = 9633
Step 58: 9633 + 169 = 9802
Step 59: 9802 + 169 = 9971
Step 60: 9971 + 169 = 10140
Step 61: 10140 + 169 = 10309
Step 62: 10309 + 169 = 10478
Step 63: 10478 + 169 = 10647
Step 64: 10647 + 169 = 10816
Step 65: 10816 + 169 = 10985
Step 66: 10985 + 169 = 11154
Step 67: 11154 + 169 = 11323
Step 68: 11323 + 169 = 11492
Step 69: 11492 + 169 = 11661
Step 70: 11661 + 169 = 11830
Step 71: 11830 + 169 = 11999
Step 72: 11999 + 169 = 12168
Step 73: 12168 + 169 = 12337
Step 74: 12337 + 169 = 12506
Step 75: 12506 + 169 = 12675
Step 76: 12675 + 169 = 12844
Step 77: 12844 + 169 = 13013
Step 78: 13013 + 169 = 13182
Step 79: 13182 + 169 = 13351
Step 80: 13351 + 169 = 13520
Step 81: 13520 + 169 = 13689
Step 82: 13689 + 169 = 13858
Step 83: 13858 + 169 = 14027
Step 84: 14027 + 169 = 14196
Step 85: 14196 + 169 = 14365
Step 86: 14365 + 169 = 14534
Step 87: 14534 + 169 = 14703
Step 88: 14703 + 169 = 14872
Step 89: 14872 + 169 = 15041
Step 90: 15041 + 169 = 15210
Step 91: 15210 + 169 = 15379

So, 169*91 = 15379