Let's roll up our sleeves and solve this. We have 800 and we're going to multiply it by 82, essentially adding 800 to itself 82 times.
Step 1: 0 + 800 = 800
Step 2: 800 + 800 = 1600
Step 3: 1600 + 800 = 2400
Step 4: 2400 + 800 = 3200
Step 5: 3200 + 800 = 4000
Step 6: 4000 + 800 = 4800
Step 7: 4800 + 800 = 5600
Step 8: 5600 + 800 = 6400
Step 9: 6400 + 800 = 7200
Step 10: 7200 + 800 = 8000
Step 11: 8000 + 800 = 8800
Step 12: 8800 + 800 = 9600
Step 13: 9600 + 800 = 10400
Step 14: 10400 + 800 = 11200
Step 15: 11200 + 800 = 12000
Step 16: 12000 + 800 = 12800
Step 17: 12800 + 800 = 13600
Step 18: 13600 + 800 = 14400
Step 19: 14400 + 800 = 15200
Step 20: 15200 + 800 = 16000
Step 21: 16000 + 800 = 16800
Step 22: 16800 + 800 = 17600
Step 23: 17600 + 800 = 18400
Step 24: 18400 + 800 = 19200
Step 25: 19200 + 800 = 20000
Step 26: 20000 + 800 = 20800
Step 27: 20800 + 800 = 21600
Step 28: 21600 + 800 = 22400
Step 29: 22400 + 800 = 23200
Step 30: 23200 + 800 = 24000
Step 31: 24000 + 800 = 24800
Step 32: 24800 + 800 = 25600
Step 33: 25600 + 800 = 26400
Step 34: 26400 + 800 = 27200
Step 35: 27200 + 800 = 28000
Step 36: 28000 + 800 = 28800
Step 37: 28800 + 800 = 29600
Step 38: 29600 + 800 = 30400
Step 39: 30400 + 800 = 31200
Step 40: 31200 + 800 = 32000
Step 41: 32000 + 800 = 32800
Step 42: 32800 + 800 = 33600
Step 43: 33600 + 800 = 34400
Step 44: 34400 + 800 = 35200
Step 45: 35200 + 800 = 36000
Step 46: 36000 + 800 = 36800
Step 47: 36800 + 800 = 37600
Step 48: 37600 + 800 = 38400
Step 49: 38400 + 800 = 39200
Step 50: 39200 + 800 = 40000
Step 51: 40000 + 800 = 40800
Step 52: 40800 + 800 = 41600
Step 53: 41600 + 800 = 42400
Step 54: 42400 + 800 = 43200
Step 55: 43200 + 800 = 44000
Step 56: 44000 + 800 = 44800
Step 57: 44800 + 800 = 45600
Step 58: 45600 + 800 = 46400
Step 59: 46400 + 800 = 47200
Step 60: 47200 + 800 = 48000
Step 61: 48000 + 800 = 48800
Step 62: 48800 + 800 = 49600
Step 63: 49600 + 800 = 50400
Step 64: 50400 + 800 = 51200
Step 65: 51200 + 800 = 52000
Step 66: 52000 + 800 = 52800
Step 67: 52800 + 800 = 53600
Step 68: 53600 + 800 = 54400
Step 69: 54400 + 800 = 55200
Step 70: 55200 + 800 = 56000
Step 71: 56000 + 800 = 56800
Step 72: 56800 + 800 = 57600
Step 73: 57600 + 800 = 58400
Step 74: 58400 + 800 = 59200
Step 75: 59200 + 800 = 60000
Step 76: 60000 + 800 = 60800
Step 77: 60800 + 800 = 61600
Step 78: 61600 + 800 = 62400
Step 79: 62400 + 800 = 63200
Step 80: 63200 + 800 = 64000
Step 81: 64000 + 800 = 64800
Step 82: 64800 + 800 = 65600

So, 800*82 = 65600