Alright, let's solve this math problem step by step. First, we have the number 225. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 81. So, we're going to take the number 225 and add it to itself 81 times.
Step 1: 0 + 225 = 225
Step 2: 225 + 225 = 450
Step 3: 450 + 225 = 675
Step 4: 675 + 225 = 900
Step 5: 900 + 225 = 1125
Step 6: 1125 + 225 = 1350
Step 7: 1350 + 225 = 1575
Step 8: 1575 + 225 = 1800
Step 9: 1800 + 225 = 2025
Step 10: 2025 + 225 = 2250
Step 11: 2250 + 225 = 2475
Step 12: 2475 + 225 = 2700
Step 13: 2700 + 225 = 2925
Step 14: 2925 + 225 = 3150
Step 15: 3150 + 225 = 3375
Step 16: 3375 + 225 = 3600
Step 17: 3600 + 225 = 3825
Step 18: 3825 + 225 = 4050
Step 19: 4050 + 225 = 4275
Step 20: 4275 + 225 = 4500
Step 21: 4500 + 225 = 4725
Step 22: 4725 + 225 = 4950
Step 23: 4950 + 225 = 5175
Step 24: 5175 + 225 = 5400
Step 25: 5400 + 225 = 5625
Step 26: 5625 + 225 = 5850
Step 27: 5850 + 225 = 6075
Step 28: 6075 + 225 = 6300
Step 29: 6300 + 225 = 6525
Step 30: 6525 + 225 = 6750
Step 31: 6750 + 225 = 6975
Step 32: 6975 + 225 = 7200
Step 33: 7200 + 225 = 7425
Step 34: 7425 + 225 = 7650
Step 35: 7650 + 225 = 7875
Step 36: 7875 + 225 = 8100
Step 37: 8100 + 225 = 8325
Step 38: 8325 + 225 = 8550
Step 39: 8550 + 225 = 8775
Step 40: 8775 + 225 = 9000
Step 41: 9000 + 225 = 9225
Step 42: 9225 + 225 = 9450
Step 43: 9450 + 225 = 9675
Step 44: 9675 + 225 = 9900
Step 45: 9900 + 225 = 10125
Step 46: 10125 + 225 = 10350
Step 47: 10350 + 225 = 10575
Step 48: 10575 + 225 = 10800
Step 49: 10800 + 225 = 11025
Step 50: 11025 + 225 = 11250
Step 51: 11250 + 225 = 11475
Step 52: 11475 + 225 = 11700
Step 53: 11700 + 225 = 11925
Step 54: 11925 + 225 = 12150
Step 55: 12150 + 225 = 12375
Step 56: 12375 + 225 = 12600
Step 57: 12600 + 225 = 12825
Step 58: 12825 + 225 = 13050
Step 59: 13050 + 225 = 13275
Step 60: 13275 + 225 = 13500
Step 61: 13500 + 225 = 13725
Step 62: 13725 + 225 = 13950
Step 63: 13950 + 225 = 14175
Step 64: 14175 + 225 = 14400
Step 65: 14400 + 225 = 14625
Step 66: 14625 + 225 = 14850
Step 67: 14850 + 225 = 15075
Step 68: 15075 + 225 = 15300
Step 69: 15300 + 225 = 15525
Step 70: 15525 + 225 = 15750
Step 71: 15750 + 225 = 15975
Step 72: 15975 + 225 = 16200
Step 73: 16200 + 225 = 16425
Step 74: 16425 + 225 = 16650
Step 75: 16650 + 225 = 16875
Step 76: 16875 + 225 = 17100
Step 77: 17100 + 225 = 17325
Step 78: 17325 + 225 = 17550
Step 79: 17550 + 225 = 17775
Step 80: 17775 + 225 = 18000
Step 81: 18000 + 225 = 18225

So, 225*81 = 18225