Without delay, let's solve this. We've got 638 and we will be multiplying it by 71, that is, adding 638 to itself 71 times.
Step 1: 0 + 638 = 638
Step 2: 638 + 638 = 1276
Step 3: 1276 + 638 = 1914
Step 4: 1914 + 638 = 2552
Step 5: 2552 + 638 = 3190
Step 6: 3190 + 638 = 3828
Step 7: 3828 + 638 = 4466
Step 8: 4466 + 638 = 5104
Step 9: 5104 + 638 = 5742
Step 10: 5742 + 638 = 6380
Step 11: 6380 + 638 = 7018
Step 12: 7018 + 638 = 7656
Step 13: 7656 + 638 = 8294
Step 14: 8294 + 638 = 8932
Step 15: 8932 + 638 = 9570
Step 16: 9570 + 638 = 10208
Step 17: 10208 + 638 = 10846
Step 18: 10846 + 638 = 11484
Step 19: 11484 + 638 = 12122
Step 20: 12122 + 638 = 12760
Step 21: 12760 + 638 = 13398
Step 22: 13398 + 638 = 14036
Step 23: 14036 + 638 = 14674
Step 24: 14674 + 638 = 15312
Step 25: 15312 + 638 = 15950
Step 26: 15950 + 638 = 16588
Step 27: 16588 + 638 = 17226
Step 28: 17226 + 638 = 17864
Step 29: 17864 + 638 = 18502
Step 30: 18502 + 638 = 19140
Step 31: 19140 + 638 = 19778
Step 32: 19778 + 638 = 20416
Step 33: 20416 + 638 = 21054
Step 34: 21054 + 638 = 21692
Step 35: 21692 + 638 = 22330
Step 36: 22330 + 638 = 22968
Step 37: 22968 + 638 = 23606
Step 38: 23606 + 638 = 24244
Step 39: 24244 + 638 = 24882
Step 40: 24882 + 638 = 25520
Step 41: 25520 + 638 = 26158
Step 42: 26158 + 638 = 26796
Step 43: 26796 + 638 = 27434
Step 44: 27434 + 638 = 28072
Step 45: 28072 + 638 = 28710
Step 46: 28710 + 638 = 29348
Step 47: 29348 + 638 = 29986
Step 48: 29986 + 638 = 30624
Step 49: 30624 + 638 = 31262
Step 50: 31262 + 638 = 31900
Step 51: 31900 + 638 = 32538
Step 52: 32538 + 638 = 33176
Step 53: 33176 + 638 = 33814
Step 54: 33814 + 638 = 34452
Step 55: 34452 + 638 = 35090
Step 56: 35090 + 638 = 35728
Step 57: 35728 + 638 = 36366
Step 58: 36366 + 638 = 37004
Step 59: 37004 + 638 = 37642
Step 60: 37642 + 638 = 38280
Step 61: 38280 + 638 = 38918
Step 62: 38918 + 638 = 39556
Step 63: 39556 + 638 = 40194
Step 64: 40194 + 638 = 40832
Step 65: 40832 + 638 = 41470
Step 66: 41470 + 638 = 42108
Step 67: 42108 + 638 = 42746
Step 68: 42746 + 638 = 43384
Step 69: 43384 + 638 = 44022
Step 70: 44022 + 638 = 44660
Step 71: 44660 + 638 = 45298

So, 638*71 = 45298