Let's roll up our sleeves and solve this. We have 720 and we're going to multiply it by 172, essentially adding 720 to itself 172 times.
Step 1: 0 + 720 = 720
Step 2: 720 + 720 = 1440
Step 3: 1440 + 720 = 2160
Step 4: 2160 + 720 = 2880
Step 5: 2880 + 720 = 3600
Step 6: 3600 + 720 = 4320
Step 7: 4320 + 720 = 5040
Step 8: 5040 + 720 = 5760
Step 9: 5760 + 720 = 6480
Step 10: 6480 + 720 = 7200
Step 11: 7200 + 720 = 7920
Step 12: 7920 + 720 = 8640
Step 13: 8640 + 720 = 9360
Step 14: 9360 + 720 = 10080
Step 15: 10080 + 720 = 10800
Step 16: 10800 + 720 = 11520
Step 17: 11520 + 720 = 12240
Step 18: 12240 + 720 = 12960
Step 19: 12960 + 720 = 13680
Step 20: 13680 + 720 = 14400
Step 21: 14400 + 720 = 15120
Step 22: 15120 + 720 = 15840
Step 23: 15840 + 720 = 16560
Step 24: 16560 + 720 = 17280
Step 25: 17280 + 720 = 18000
Step 26: 18000 + 720 = 18720
Step 27: 18720 + 720 = 19440
Step 28: 19440 + 720 = 20160
Step 29: 20160 + 720 = 20880
Step 30: 20880 + 720 = 21600
Step 31: 21600 + 720 = 22320
Step 32: 22320 + 720 = 23040
Step 33: 23040 + 720 = 23760
Step 34: 23760 + 720 = 24480
Step 35: 24480 + 720 = 25200
Step 36: 25200 + 720 = 25920
Step 37: 25920 + 720 = 26640
Step 38: 26640 + 720 = 27360
Step 39: 27360 + 720 = 28080
Step 40: 28080 + 720 = 28800
Step 41: 28800 + 720 = 29520
Step 42: 29520 + 720 = 30240
Step 43: 30240 + 720 = 30960
Step 44: 30960 + 720 = 31680
Step 45: 31680 + 720 = 32400
Step 46: 32400 + 720 = 33120
Step 47: 33120 + 720 = 33840
Step 48: 33840 + 720 = 34560
Step 49: 34560 + 720 = 35280
Step 50: 35280 + 720 = 36000
Step 51: 36000 + 720 = 36720
Step 52: 36720 + 720 = 37440
Step 53: 37440 + 720 = 38160
Step 54: 38160 + 720 = 38880
Step 55: 38880 + 720 = 39600
Step 56: 39600 + 720 = 40320
Step 57: 40320 + 720 = 41040
Step 58: 41040 + 720 = 41760
Step 59: 41760 + 720 = 42480
Step 60: 42480 + 720 = 43200
Step 61: 43200 + 720 = 43920
Step 62: 43920 + 720 = 44640
Step 63: 44640 + 720 = 45360
Step 64: 45360 + 720 = 46080
Step 65: 46080 + 720 = 46800
Step 66: 46800 + 720 = 47520
Step 67: 47520 + 720 = 48240
Step 68: 48240 + 720 = 48960
Step 69: 48960 + 720 = 49680
Step 70: 49680 + 720 = 50400
Step 71: 50400 + 720 = 51120
Step 72: 51120 + 720 = 51840
Step 73: 51840 + 720 = 52560
Step 74: 52560 + 720 = 53280
Step 75: 53280 + 720 = 54000
Step 76: 54000 + 720 = 54720
Step 77: 54720 + 720 = 55440
Step 78: 55440 + 720 = 56160
Step 79: 56160 + 720 = 56880
Step 80: 56880 + 720 = 57600
Step 81: 57600 + 720 = 58320
Step 82: 58320 + 720 = 59040
Step 83: 59040 + 720 = 59760
Step 84: 59760 + 720 = 60480
Step 85: 60480 + 720 = 61200
Step 86: 61200 + 720 = 61920
Step 87: 61920 + 720 = 62640
Step 88: 62640 + 720 = 63360
Step 89: 63360 + 720 = 64080
Step 90: 64080 + 720 = 64800
Step 91: 64800 + 720 = 65520
Step 92: 65520 + 720 = 66240
Step 93: 66240 + 720 = 66960
Step 94: 66960 + 720 = 67680
Step 95: 67680 + 720 = 68400
Step 96: 68400 + 720 = 69120
Step 97: 69120 + 720 = 69840
Step 98: 69840 + 720 = 70560
Step 99: 70560 + 720 = 71280
Step 100: 71280 + 720 = 72000
Step 101: 72000 + 720 = 72720
Step 102: 72720 + 720 = 73440
Step 103: 73440 + 720 = 74160
Step 104: 74160 + 720 = 74880
Step 105: 74880 + 720 = 75600
Step 106: 75600 + 720 = 76320
Step 107: 76320 + 720 = 77040
Step 108: 77040 + 720 = 77760
Step 109: 77760 + 720 = 78480
Step 110: 78480 + 720 = 79200
Step 111: 79200 + 720 = 79920
Step 112: 79920 + 720 = 80640
Step 113: 80640 + 720 = 81360
Step 114: 81360 + 720 = 82080
Step 115: 82080 + 720 = 82800
Step 116: 82800 + 720 = 83520
Step 117: 83520 + 720 = 84240
Step 118: 84240 + 720 = 84960
Step 119: 84960 + 720 = 85680
Step 120: 85680 + 720 = 86400
Step 121: 86400 + 720 = 87120
Step 122: 87120 + 720 = 87840
Step 123: 87840 + 720 = 88560
Step 124: 88560 + 720 = 89280
Step 125: 89280 + 720 = 90000
Step 126: 90000 + 720 = 90720
Step 127: 90720 + 720 = 91440
Step 128: 91440 + 720 = 92160
Step 129: 92160 + 720 = 92880
Step 130: 92880 + 720 = 93600
Step 131: 93600 + 720 = 94320
Step 132: 94320 + 720 = 95040
Step 133: 95040 + 720 = 95760
Step 134: 95760 + 720 = 96480
Step 135: 96480 + 720 = 97200
Step 136: 97200 + 720 = 97920
Step 137: 97920 + 720 = 98640
Step 138: 98640 + 720 = 99360
Step 139: 99360 + 720 = 100080
Step 140: 100080 + 720 = 100800
Step 141: 100800 + 720 = 101520
Step 142: 101520 + 720 = 102240
Step 143: 102240 + 720 = 102960
Step 144: 102960 + 720 = 103680
Step 145: 103680 + 720 = 104400
Step 146: 104400 + 720 = 105120
Step 147: 105120 + 720 = 105840
Step 148: 105840 + 720 = 106560
Step 149: 106560 + 720 = 107280
Step 150: 107280 + 720 = 108000
Step 151: 108000 + 720 = 108720
Step 152: 108720 + 720 = 109440
Step 153: 109440 + 720 = 110160
Step 154: 110160 + 720 = 110880
Step 155: 110880 + 720 = 111600
Step 156: 111600 + 720 = 112320
Step 157: 112320 + 720 = 113040
Step 158: 113040 + 720 = 113760
Step 159: 113760 + 720 = 114480
Step 160: 114480 + 720 = 115200
Step 161: 115200 + 720 = 115920
Step 162: 115920 + 720 = 116640
Step 163: 116640 + 720 = 117360
Step 164: 117360 + 720 = 118080
Step 165: 118080 + 720 = 118800
Step 166: 118800 + 720 = 119520
Step 167: 119520 + 720 = 120240
Step 168: 120240 + 720 = 120960
Step 169: 120960 + 720 = 121680
Step 170: 121680 + 720 = 122400
Step 171: 122400 + 720 = 123120
Step 172: 123120 + 720 = 123840

So, 720*172 = 123840