Alright, let's solve this math problem step by step. First, we have the number 120. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 172. So, we're going to take the number 120 and add it to itself 172 times.
Step 1: 0 + 120 = 120
Step 2: 120 + 120 = 240
Step 3: 240 + 120 = 360
Step 4: 360 + 120 = 480
Step 5: 480 + 120 = 600
Step 6: 600 + 120 = 720
Step 7: 720 + 120 = 840
Step 8: 840 + 120 = 960
Step 9: 960 + 120 = 1080
Step 10: 1080 + 120 = 1200
Step 11: 1200 + 120 = 1320
Step 12: 1320 + 120 = 1440
Step 13: 1440 + 120 = 1560
Step 14: 1560 + 120 = 1680
Step 15: 1680 + 120 = 1800
Step 16: 1800 + 120 = 1920
Step 17: 1920 + 120 = 2040
Step 18: 2040 + 120 = 2160
Step 19: 2160 + 120 = 2280
Step 20: 2280 + 120 = 2400
Step 21: 2400 + 120 = 2520
Step 22: 2520 + 120 = 2640
Step 23: 2640 + 120 = 2760
Step 24: 2760 + 120 = 2880
Step 25: 2880 + 120 = 3000
Step 26: 3000 + 120 = 3120
Step 27: 3120 + 120 = 3240
Step 28: 3240 + 120 = 3360
Step 29: 3360 + 120 = 3480
Step 30: 3480 + 120 = 3600
Step 31: 3600 + 120 = 3720
Step 32: 3720 + 120 = 3840
Step 33: 3840 + 120 = 3960
Step 34: 3960 + 120 = 4080
Step 35: 4080 + 120 = 4200
Step 36: 4200 + 120 = 4320
Step 37: 4320 + 120 = 4440
Step 38: 4440 + 120 = 4560
Step 39: 4560 + 120 = 4680
Step 40: 4680 + 120 = 4800
Step 41: 4800 + 120 = 4920
Step 42: 4920 + 120 = 5040
Step 43: 5040 + 120 = 5160
Step 44: 5160 + 120 = 5280
Step 45: 5280 + 120 = 5400
Step 46: 5400 + 120 = 5520
Step 47: 5520 + 120 = 5640
Step 48: 5640 + 120 = 5760
Step 49: 5760 + 120 = 5880
Step 50: 5880 + 120 = 6000
Step 51: 6000 + 120 = 6120
Step 52: 6120 + 120 = 6240
Step 53: 6240 + 120 = 6360
Step 54: 6360 + 120 = 6480
Step 55: 6480 + 120 = 6600
Step 56: 6600 + 120 = 6720
Step 57: 6720 + 120 = 6840
Step 58: 6840 + 120 = 6960
Step 59: 6960 + 120 = 7080
Step 60: 7080 + 120 = 7200
Step 61: 7200 + 120 = 7320
Step 62: 7320 + 120 = 7440
Step 63: 7440 + 120 = 7560
Step 64: 7560 + 120 = 7680
Step 65: 7680 + 120 = 7800
Step 66: 7800 + 120 = 7920
Step 67: 7920 + 120 = 8040
Step 68: 8040 + 120 = 8160
Step 69: 8160 + 120 = 8280
Step 70: 8280 + 120 = 8400
Step 71: 8400 + 120 = 8520
Step 72: 8520 + 120 = 8640
Step 73: 8640 + 120 = 8760
Step 74: 8760 + 120 = 8880
Step 75: 8880 + 120 = 9000
Step 76: 9000 + 120 = 9120
Step 77: 9120 + 120 = 9240
Step 78: 9240 + 120 = 9360
Step 79: 9360 + 120 = 9480
Step 80: 9480 + 120 = 9600
Step 81: 9600 + 120 = 9720
Step 82: 9720 + 120 = 9840
Step 83: 9840 + 120 = 9960
Step 84: 9960 + 120 = 10080
Step 85: 10080 + 120 = 10200
Step 86: 10200 + 120 = 10320
Step 87: 10320 + 120 = 10440
Step 88: 10440 + 120 = 10560
Step 89: 10560 + 120 = 10680
Step 90: 10680 + 120 = 10800
Step 91: 10800 + 120 = 10920
Step 92: 10920 + 120 = 11040
Step 93: 11040 + 120 = 11160
Step 94: 11160 + 120 = 11280
Step 95: 11280 + 120 = 11400
Step 96: 11400 + 120 = 11520
Step 97: 11520 + 120 = 11640
Step 98: 11640 + 120 = 11760
Step 99: 11760 + 120 = 11880
Step 100: 11880 + 120 = 12000
Step 101: 12000 + 120 = 12120
Step 102: 12120 + 120 = 12240
Step 103: 12240 + 120 = 12360
Step 104: 12360 + 120 = 12480
Step 105: 12480 + 120 = 12600
Step 106: 12600 + 120 = 12720
Step 107: 12720 + 120 = 12840
Step 108: 12840 + 120 = 12960
Step 109: 12960 + 120 = 13080
Step 110: 13080 + 120 = 13200
Step 111: 13200 + 120 = 13320
Step 112: 13320 + 120 = 13440
Step 113: 13440 + 120 = 13560
Step 114: 13560 + 120 = 13680
Step 115: 13680 + 120 = 13800
Step 116: 13800 + 120 = 13920
Step 117: 13920 + 120 = 14040
Step 118: 14040 + 120 = 14160
Step 119: 14160 + 120 = 14280
Step 120: 14280 + 120 = 14400
Step 121: 14400 + 120 = 14520
Step 122: 14520 + 120 = 14640
Step 123: 14640 + 120 = 14760
Step 124: 14760 + 120 = 14880
Step 125: 14880 + 120 = 15000
Step 126: 15000 + 120 = 15120
Step 127: 15120 + 120 = 15240
Step 128: 15240 + 120 = 15360
Step 129: 15360 + 120 = 15480
Step 130: 15480 + 120 = 15600
Step 131: 15600 + 120 = 15720
Step 132: 15720 + 120 = 15840
Step 133: 15840 + 120 = 15960
Step 134: 15960 + 120 = 16080
Step 135: 16080 + 120 = 16200
Step 136: 16200 + 120 = 16320
Step 137: 16320 + 120 = 16440
Step 138: 16440 + 120 = 16560
Step 139: 16560 + 120 = 16680
Step 140: 16680 + 120 = 16800
Step 141: 16800 + 120 = 16920
Step 142: 16920 + 120 = 17040
Step 143: 17040 + 120 = 17160
Step 144: 17160 + 120 = 17280
Step 145: 17280 + 120 = 17400
Step 146: 17400 + 120 = 17520
Step 147: 17520 + 120 = 17640
Step 148: 17640 + 120 = 17760
Step 149: 17760 + 120 = 17880
Step 150: 17880 + 120 = 18000
Step 151: 18000 + 120 = 18120
Step 152: 18120 + 120 = 18240
Step 153: 18240 + 120 = 18360
Step 154: 18360 + 120 = 18480
Step 155: 18480 + 120 = 18600
Step 156: 18600 + 120 = 18720
Step 157: 18720 + 120 = 18840
Step 158: 18840 + 120 = 18960
Step 159: 18960 + 120 = 19080
Step 160: 19080 + 120 = 19200
Step 161: 19200 + 120 = 19320
Step 162: 19320 + 120 = 19440
Step 163: 19440 + 120 = 19560
Step 164: 19560 + 120 = 19680
Step 165: 19680 + 120 = 19800
Step 166: 19800 + 120 = 19920
Step 167: 19920 + 120 = 20040
Step 168: 20040 + 120 = 20160
Step 169: 20160 + 120 = 20280
Step 170: 20280 + 120 = 20400
Step 171: 20400 + 120 = 20520
Step 172: 20520 + 120 = 20640

So, 120*172 = 20640