OK, let's crack this. We're given 678 and our task is to multiply it by 70. Essentially, we'll be adding 678 to itself 70 times.
Step 1: 0 + 678 = 678
Step 2: 678 + 678 = 1356
Step 3: 1356 + 678 = 2034
Step 4: 2034 + 678 = 2712
Step 5: 2712 + 678 = 3390
Step 6: 3390 + 678 = 4068
Step 7: 4068 + 678 = 4746
Step 8: 4746 + 678 = 5424
Step 9: 5424 + 678 = 6102
Step 10: 6102 + 678 = 6780
Step 11: 6780 + 678 = 7458
Step 12: 7458 + 678 = 8136
Step 13: 8136 + 678 = 8814
Step 14: 8814 + 678 = 9492
Step 15: 9492 + 678 = 10170
Step 16: 10170 + 678 = 10848
Step 17: 10848 + 678 = 11526
Step 18: 11526 + 678 = 12204
Step 19: 12204 + 678 = 12882
Step 20: 12882 + 678 = 13560
Step 21: 13560 + 678 = 14238
Step 22: 14238 + 678 = 14916
Step 23: 14916 + 678 = 15594
Step 24: 15594 + 678 = 16272
Step 25: 16272 + 678 = 16950
Step 26: 16950 + 678 = 17628
Step 27: 17628 + 678 = 18306
Step 28: 18306 + 678 = 18984
Step 29: 18984 + 678 = 19662
Step 30: 19662 + 678 = 20340
Step 31: 20340 + 678 = 21018
Step 32: 21018 + 678 = 21696
Step 33: 21696 + 678 = 22374
Step 34: 22374 + 678 = 23052
Step 35: 23052 + 678 = 23730
Step 36: 23730 + 678 = 24408
Step 37: 24408 + 678 = 25086
Step 38: 25086 + 678 = 25764
Step 39: 25764 + 678 = 26442
Step 40: 26442 + 678 = 27120
Step 41: 27120 + 678 = 27798
Step 42: 27798 + 678 = 28476
Step 43: 28476 + 678 = 29154
Step 44: 29154 + 678 = 29832
Step 45: 29832 + 678 = 30510
Step 46: 30510 + 678 = 31188
Step 47: 31188 + 678 = 31866
Step 48: 31866 + 678 = 32544
Step 49: 32544 + 678 = 33222
Step 50: 33222 + 678 = 33900
Step 51: 33900 + 678 = 34578
Step 52: 34578 + 678 = 35256
Step 53: 35256 + 678 = 35934
Step 54: 35934 + 678 = 36612
Step 55: 36612 + 678 = 37290
Step 56: 37290 + 678 = 37968
Step 57: 37968 + 678 = 38646
Step 58: 38646 + 678 = 39324
Step 59: 39324 + 678 = 40002
Step 60: 40002 + 678 = 40680
Step 61: 40680 + 678 = 41358
Step 62: 41358 + 678 = 42036
Step 63: 42036 + 678 = 42714
Step 64: 42714 + 678 = 43392
Step 65: 43392 + 678 = 44070
Step 66: 44070 + 678 = 44748
Step 67: 44748 + 678 = 45426
Step 68: 45426 + 678 = 46104
Step 69: 46104 + 678 = 46782
Step 70: 46782 + 678 = 47460

So, 678*70 = 47460