Without delay, let's solve this. We've got 428 and we will be multiplying it by 81, that is, adding 428 to itself 81 times.
Step 1: 0 + 428 = 428
Step 2: 428 + 428 = 856
Step 3: 856 + 428 = 1284
Step 4: 1284 + 428 = 1712
Step 5: 1712 + 428 = 2140
Step 6: 2140 + 428 = 2568
Step 7: 2568 + 428 = 2996
Step 8: 2996 + 428 = 3424
Step 9: 3424 + 428 = 3852
Step 10: 3852 + 428 = 4280
Step 11: 4280 + 428 = 4708
Step 12: 4708 + 428 = 5136
Step 13: 5136 + 428 = 5564
Step 14: 5564 + 428 = 5992
Step 15: 5992 + 428 = 6420
Step 16: 6420 + 428 = 6848
Step 17: 6848 + 428 = 7276
Step 18: 7276 + 428 = 7704
Step 19: 7704 + 428 = 8132
Step 20: 8132 + 428 = 8560
Step 21: 8560 + 428 = 8988
Step 22: 8988 + 428 = 9416
Step 23: 9416 + 428 = 9844
Step 24: 9844 + 428 = 10272
Step 25: 10272 + 428 = 10700
Step 26: 10700 + 428 = 11128
Step 27: 11128 + 428 = 11556
Step 28: 11556 + 428 = 11984
Step 29: 11984 + 428 = 12412
Step 30: 12412 + 428 = 12840
Step 31: 12840 + 428 = 13268
Step 32: 13268 + 428 = 13696
Step 33: 13696 + 428 = 14124
Step 34: 14124 + 428 = 14552
Step 35: 14552 + 428 = 14980
Step 36: 14980 + 428 = 15408
Step 37: 15408 + 428 = 15836
Step 38: 15836 + 428 = 16264
Step 39: 16264 + 428 = 16692
Step 40: 16692 + 428 = 17120
Step 41: 17120 + 428 = 17548
Step 42: 17548 + 428 = 17976
Step 43: 17976 + 428 = 18404
Step 44: 18404 + 428 = 18832
Step 45: 18832 + 428 = 19260
Step 46: 19260 + 428 = 19688
Step 47: 19688 + 428 = 20116
Step 48: 20116 + 428 = 20544
Step 49: 20544 + 428 = 20972
Step 50: 20972 + 428 = 21400
Step 51: 21400 + 428 = 21828
Step 52: 21828 + 428 = 22256
Step 53: 22256 + 428 = 22684
Step 54: 22684 + 428 = 23112
Step 55: 23112 + 428 = 23540
Step 56: 23540 + 428 = 23968
Step 57: 23968 + 428 = 24396
Step 58: 24396 + 428 = 24824
Step 59: 24824 + 428 = 25252
Step 60: 25252 + 428 = 25680
Step 61: 25680 + 428 = 26108
Step 62: 26108 + 428 = 26536
Step 63: 26536 + 428 = 26964
Step 64: 26964 + 428 = 27392
Step 65: 27392 + 428 = 27820
Step 66: 27820 + 428 = 28248
Step 67: 28248 + 428 = 28676
Step 68: 28676 + 428 = 29104
Step 69: 29104 + 428 = 29532
Step 70: 29532 + 428 = 29960
Step 71: 29960 + 428 = 30388
Step 72: 30388 + 428 = 30816
Step 73: 30816 + 428 = 31244
Step 74: 31244 + 428 = 31672
Step 75: 31672 + 428 = 32100
Step 76: 32100 + 428 = 32528
Step 77: 32528 + 428 = 32956
Step 78: 32956 + 428 = 33384
Step 79: 33384 + 428 = 33812
Step 80: 33812 + 428 = 34240
Step 81: 34240 + 428 = 34668

So, 428*81 = 34668