Let's roll up our sleeves and solve this. We have 851 and we're going to multiply it by 72, essentially adding 851 to itself 72 times.
Step 1: 0 + 851 = 851
Step 2: 851 + 851 = 1702
Step 3: 1702 + 851 = 2553
Step 4: 2553 + 851 = 3404
Step 5: 3404 + 851 = 4255
Step 6: 4255 + 851 = 5106
Step 7: 5106 + 851 = 5957
Step 8: 5957 + 851 = 6808
Step 9: 6808 + 851 = 7659
Step 10: 7659 + 851 = 8510
Step 11: 8510 + 851 = 9361
Step 12: 9361 + 851 = 10212
Step 13: 10212 + 851 = 11063
Step 14: 11063 + 851 = 11914
Step 15: 11914 + 851 = 12765
Step 16: 12765 + 851 = 13616
Step 17: 13616 + 851 = 14467
Step 18: 14467 + 851 = 15318
Step 19: 15318 + 851 = 16169
Step 20: 16169 + 851 = 17020
Step 21: 17020 + 851 = 17871
Step 22: 17871 + 851 = 18722
Step 23: 18722 + 851 = 19573
Step 24: 19573 + 851 = 20424
Step 25: 20424 + 851 = 21275
Step 26: 21275 + 851 = 22126
Step 27: 22126 + 851 = 22977
Step 28: 22977 + 851 = 23828
Step 29: 23828 + 851 = 24679
Step 30: 24679 + 851 = 25530
Step 31: 25530 + 851 = 26381
Step 32: 26381 + 851 = 27232
Step 33: 27232 + 851 = 28083
Step 34: 28083 + 851 = 28934
Step 35: 28934 + 851 = 29785
Step 36: 29785 + 851 = 30636
Step 37: 30636 + 851 = 31487
Step 38: 31487 + 851 = 32338
Step 39: 32338 + 851 = 33189
Step 40: 33189 + 851 = 34040
Step 41: 34040 + 851 = 34891
Step 42: 34891 + 851 = 35742
Step 43: 35742 + 851 = 36593
Step 44: 36593 + 851 = 37444
Step 45: 37444 + 851 = 38295
Step 46: 38295 + 851 = 39146
Step 47: 39146 + 851 = 39997
Step 48: 39997 + 851 = 40848
Step 49: 40848 + 851 = 41699
Step 50: 41699 + 851 = 42550
Step 51: 42550 + 851 = 43401
Step 52: 43401 + 851 = 44252
Step 53: 44252 + 851 = 45103
Step 54: 45103 + 851 = 45954
Step 55: 45954 + 851 = 46805
Step 56: 46805 + 851 = 47656
Step 57: 47656 + 851 = 48507
Step 58: 48507 + 851 = 49358
Step 59: 49358 + 851 = 50209
Step 60: 50209 + 851 = 51060
Step 61: 51060 + 851 = 51911
Step 62: 51911 + 851 = 52762
Step 63: 52762 + 851 = 53613
Step 64: 53613 + 851 = 54464
Step 65: 54464 + 851 = 55315
Step 66: 55315 + 851 = 56166
Step 67: 56166 + 851 = 57017
Step 68: 57017 + 851 = 57868
Step 69: 57868 + 851 = 58719
Step 70: 58719 + 851 = 59570
Step 71: 59570 + 851 = 60421
Step 72: 60421 + 851 = 61272

So, 851*72 = 61272