Let's roll up our sleeves and solve this. We have 75 and we're going to multiply it by 129, essentially adding 75 to itself 129 times.
Step 1: 0 + 75 = 75
Step 2: 75 + 75 = 150
Step 3: 150 + 75 = 225
Step 4: 225 + 75 = 300
Step 5: 300 + 75 = 375
Step 6: 375 + 75 = 450
Step 7: 450 + 75 = 525
Step 8: 525 + 75 = 600
Step 9: 600 + 75 = 675
Step 10: 675 + 75 = 750
Step 11: 750 + 75 = 825
Step 12: 825 + 75 = 900
Step 13: 900 + 75 = 975
Step 14: 975 + 75 = 1050
Step 15: 1050 + 75 = 1125
Step 16: 1125 + 75 = 1200
Step 17: 1200 + 75 = 1275
Step 18: 1275 + 75 = 1350
Step 19: 1350 + 75 = 1425
Step 20: 1425 + 75 = 1500
Step 21: 1500 + 75 = 1575
Step 22: 1575 + 75 = 1650
Step 23: 1650 + 75 = 1725
Step 24: 1725 + 75 = 1800
Step 25: 1800 + 75 = 1875
Step 26: 1875 + 75 = 1950
Step 27: 1950 + 75 = 2025
Step 28: 2025 + 75 = 2100
Step 29: 2100 + 75 = 2175
Step 30: 2175 + 75 = 2250
Step 31: 2250 + 75 = 2325
Step 32: 2325 + 75 = 2400
Step 33: 2400 + 75 = 2475
Step 34: 2475 + 75 = 2550
Step 35: 2550 + 75 = 2625
Step 36: 2625 + 75 = 2700
Step 37: 2700 + 75 = 2775
Step 38: 2775 + 75 = 2850
Step 39: 2850 + 75 = 2925
Step 40: 2925 + 75 = 3000
Step 41: 3000 + 75 = 3075
Step 42: 3075 + 75 = 3150
Step 43: 3150 + 75 = 3225
Step 44: 3225 + 75 = 3300
Step 45: 3300 + 75 = 3375
Step 46: 3375 + 75 = 3450
Step 47: 3450 + 75 = 3525
Step 48: 3525 + 75 = 3600
Step 49: 3600 + 75 = 3675
Step 50: 3675 + 75 = 3750
Step 51: 3750 + 75 = 3825
Step 52: 3825 + 75 = 3900
Step 53: 3900 + 75 = 3975
Step 54: 3975 + 75 = 4050
Step 55: 4050 + 75 = 4125
Step 56: 4125 + 75 = 4200
Step 57: 4200 + 75 = 4275
Step 58: 4275 + 75 = 4350
Step 59: 4350 + 75 = 4425
Step 60: 4425 + 75 = 4500
Step 61: 4500 + 75 = 4575
Step 62: 4575 + 75 = 4650
Step 63: 4650 + 75 = 4725
Step 64: 4725 + 75 = 4800
Step 65: 4800 + 75 = 4875
Step 66: 4875 + 75 = 4950
Step 67: 4950 + 75 = 5025
Step 68: 5025 + 75 = 5100
Step 69: 5100 + 75 = 5175
Step 70: 5175 + 75 = 5250
Step 71: 5250 + 75 = 5325
Step 72: 5325 + 75 = 5400
Step 73: 5400 + 75 = 5475
Step 74: 5475 + 75 = 5550
Step 75: 5550 + 75 = 5625
Step 76: 5625 + 75 = 5700
Step 77: 5700 + 75 = 5775
Step 78: 5775 + 75 = 5850
Step 79: 5850 + 75 = 5925
Step 80: 5925 + 75 = 6000
Step 81: 6000 + 75 = 6075
Step 82: 6075 + 75 = 6150
Step 83: 6150 + 75 = 6225
Step 84: 6225 + 75 = 6300
Step 85: 6300 + 75 = 6375
Step 86: 6375 + 75 = 6450
Step 87: 6450 + 75 = 6525
Step 88: 6525 + 75 = 6600
Step 89: 6600 + 75 = 6675
Step 90: 6675 + 75 = 6750
Step 91: 6750 + 75 = 6825
Step 92: 6825 + 75 = 6900
Step 93: 6900 + 75 = 6975
Step 94: 6975 + 75 = 7050
Step 95: 7050 + 75 = 7125
Step 96: 7125 + 75 = 7200
Step 97: 7200 + 75 = 7275
Step 98: 7275 + 75 = 7350
Step 99: 7350 + 75 = 7425
Step 100: 7425 + 75 = 7500
Step 101: 7500 + 75 = 7575
Step 102: 7575 + 75 = 7650
Step 103: 7650 + 75 = 7725
Step 104: 7725 + 75 = 7800
Step 105: 7800 + 75 = 7875
Step 106: 7875 + 75 = 7950
Step 107: 7950 + 75 = 8025
Step 108: 8025 + 75 = 8100
Step 109: 8100 + 75 = 8175
Step 110: 8175 + 75 = 8250
Step 111: 8250 + 75 = 8325
Step 112: 8325 + 75 = 8400
Step 113: 8400 + 75 = 8475
Step 114: 8475 + 75 = 8550
Step 115: 8550 + 75 = 8625
Step 116: 8625 + 75 = 8700
Step 117: 8700 + 75 = 8775
Step 118: 8775 + 75 = 8850
Step 119: 8850 + 75 = 8925
Step 120: 8925 + 75 = 9000
Step 121: 9000 + 75 = 9075
Step 122: 9075 + 75 = 9150
Step 123: 9150 + 75 = 9225
Step 124: 9225 + 75 = 9300
Step 125: 9300 + 75 = 9375
Step 126: 9375 + 75 = 9450
Step 127: 9450 + 75 = 9525
Step 128: 9525 + 75 = 9600
Step 129: 9600 + 75 = 9675

So, 75*129 = 9675