Let's roll up our sleeves and solve this. We have 251 and we're going to multiply it by 71, essentially adding 251 to itself 71 times.
Step 1: 0 + 251 = 251
Step 2: 251 + 251 = 502
Step 3: 502 + 251 = 753
Step 4: 753 + 251 = 1004
Step 5: 1004 + 251 = 1255
Step 6: 1255 + 251 = 1506
Step 7: 1506 + 251 = 1757
Step 8: 1757 + 251 = 2008
Step 9: 2008 + 251 = 2259
Step 10: 2259 + 251 = 2510
Step 11: 2510 + 251 = 2761
Step 12: 2761 + 251 = 3012
Step 13: 3012 + 251 = 3263
Step 14: 3263 + 251 = 3514
Step 15: 3514 + 251 = 3765
Step 16: 3765 + 251 = 4016
Step 17: 4016 + 251 = 4267
Step 18: 4267 + 251 = 4518
Step 19: 4518 + 251 = 4769
Step 20: 4769 + 251 = 5020
Step 21: 5020 + 251 = 5271
Step 22: 5271 + 251 = 5522
Step 23: 5522 + 251 = 5773
Step 24: 5773 + 251 = 6024
Step 25: 6024 + 251 = 6275
Step 26: 6275 + 251 = 6526
Step 27: 6526 + 251 = 6777
Step 28: 6777 + 251 = 7028
Step 29: 7028 + 251 = 7279
Step 30: 7279 + 251 = 7530
Step 31: 7530 + 251 = 7781
Step 32: 7781 + 251 = 8032
Step 33: 8032 + 251 = 8283
Step 34: 8283 + 251 = 8534
Step 35: 8534 + 251 = 8785
Step 36: 8785 + 251 = 9036
Step 37: 9036 + 251 = 9287
Step 38: 9287 + 251 = 9538
Step 39: 9538 + 251 = 9789
Step 40: 9789 + 251 = 10040
Step 41: 10040 + 251 = 10291
Step 42: 10291 + 251 = 10542
Step 43: 10542 + 251 = 10793
Step 44: 10793 + 251 = 11044
Step 45: 11044 + 251 = 11295
Step 46: 11295 + 251 = 11546
Step 47: 11546 + 251 = 11797
Step 48: 11797 + 251 = 12048
Step 49: 12048 + 251 = 12299
Step 50: 12299 + 251 = 12550
Step 51: 12550 + 251 = 12801
Step 52: 12801 + 251 = 13052
Step 53: 13052 + 251 = 13303
Step 54: 13303 + 251 = 13554
Step 55: 13554 + 251 = 13805
Step 56: 13805 + 251 = 14056
Step 57: 14056 + 251 = 14307
Step 58: 14307 + 251 = 14558
Step 59: 14558 + 251 = 14809
Step 60: 14809 + 251 = 15060
Step 61: 15060 + 251 = 15311
Step 62: 15311 + 251 = 15562
Step 63: 15562 + 251 = 15813
Step 64: 15813 + 251 = 16064
Step 65: 16064 + 251 = 16315
Step 66: 16315 + 251 = 16566
Step 67: 16566 + 251 = 16817
Step 68: 16817 + 251 = 17068
Step 69: 17068 + 251 = 17319
Step 70: 17319 + 251 = 17570
Step 71: 17570 + 251 = 17821

So, 251*71 = 17821