Without delay, let's solve this. We've got 852 and we will be multiplying it by 80, that is, adding 852 to itself 80 times.
Step 1: 0 + 852 = 852
Step 2: 852 + 852 = 1704
Step 3: 1704 + 852 = 2556
Step 4: 2556 + 852 = 3408
Step 5: 3408 + 852 = 4260
Step 6: 4260 + 852 = 5112
Step 7: 5112 + 852 = 5964
Step 8: 5964 + 852 = 6816
Step 9: 6816 + 852 = 7668
Step 10: 7668 + 852 = 8520
Step 11: 8520 + 852 = 9372
Step 12: 9372 + 852 = 10224
Step 13: 10224 + 852 = 11076
Step 14: 11076 + 852 = 11928
Step 15: 11928 + 852 = 12780
Step 16: 12780 + 852 = 13632
Step 17: 13632 + 852 = 14484
Step 18: 14484 + 852 = 15336
Step 19: 15336 + 852 = 16188
Step 20: 16188 + 852 = 17040
Step 21: 17040 + 852 = 17892
Step 22: 17892 + 852 = 18744
Step 23: 18744 + 852 = 19596
Step 24: 19596 + 852 = 20448
Step 25: 20448 + 852 = 21300
Step 26: 21300 + 852 = 22152
Step 27: 22152 + 852 = 23004
Step 28: 23004 + 852 = 23856
Step 29: 23856 + 852 = 24708
Step 30: 24708 + 852 = 25560
Step 31: 25560 + 852 = 26412
Step 32: 26412 + 852 = 27264
Step 33: 27264 + 852 = 28116
Step 34: 28116 + 852 = 28968
Step 35: 28968 + 852 = 29820
Step 36: 29820 + 852 = 30672
Step 37: 30672 + 852 = 31524
Step 38: 31524 + 852 = 32376
Step 39: 32376 + 852 = 33228
Step 40: 33228 + 852 = 34080
Step 41: 34080 + 852 = 34932
Step 42: 34932 + 852 = 35784
Step 43: 35784 + 852 = 36636
Step 44: 36636 + 852 = 37488
Step 45: 37488 + 852 = 38340
Step 46: 38340 + 852 = 39192
Step 47: 39192 + 852 = 40044
Step 48: 40044 + 852 = 40896
Step 49: 40896 + 852 = 41748
Step 50: 41748 + 852 = 42600
Step 51: 42600 + 852 = 43452
Step 52: 43452 + 852 = 44304
Step 53: 44304 + 852 = 45156
Step 54: 45156 + 852 = 46008
Step 55: 46008 + 852 = 46860
Step 56: 46860 + 852 = 47712
Step 57: 47712 + 852 = 48564
Step 58: 48564 + 852 = 49416
Step 59: 49416 + 852 = 50268
Step 60: 50268 + 852 = 51120
Step 61: 51120 + 852 = 51972
Step 62: 51972 + 852 = 52824
Step 63: 52824 + 852 = 53676
Step 64: 53676 + 852 = 54528
Step 65: 54528 + 852 = 55380
Step 66: 55380 + 852 = 56232
Step 67: 56232 + 852 = 57084
Step 68: 57084 + 852 = 57936
Step 69: 57936 + 852 = 58788
Step 70: 58788 + 852 = 59640
Step 71: 59640 + 852 = 60492
Step 72: 60492 + 852 = 61344
Step 73: 61344 + 852 = 62196
Step 74: 62196 + 852 = 63048
Step 75: 63048 + 852 = 63900
Step 76: 63900 + 852 = 64752
Step 77: 64752 + 852 = 65604
Step 78: 65604 + 852 = 66456
Step 79: 66456 + 852 = 67308
Step 80: 67308 + 852 = 68160

So, 852*80 = 68160