Without delay, let's solve this. We've got 423 and we will be multiplying it by 67, that is, adding 423 to itself 67 times.
Step 1: 0 + 423 = 423
Step 2: 423 + 423 = 846
Step 3: 846 + 423 = 1269
Step 4: 1269 + 423 = 1692
Step 5: 1692 + 423 = 2115
Step 6: 2115 + 423 = 2538
Step 7: 2538 + 423 = 2961
Step 8: 2961 + 423 = 3384
Step 9: 3384 + 423 = 3807
Step 10: 3807 + 423 = 4230
Step 11: 4230 + 423 = 4653
Step 12: 4653 + 423 = 5076
Step 13: 5076 + 423 = 5499
Step 14: 5499 + 423 = 5922
Step 15: 5922 + 423 = 6345
Step 16: 6345 + 423 = 6768
Step 17: 6768 + 423 = 7191
Step 18: 7191 + 423 = 7614
Step 19: 7614 + 423 = 8037
Step 20: 8037 + 423 = 8460
Step 21: 8460 + 423 = 8883
Step 22: 8883 + 423 = 9306
Step 23: 9306 + 423 = 9729
Step 24: 9729 + 423 = 10152
Step 25: 10152 + 423 = 10575
Step 26: 10575 + 423 = 10998
Step 27: 10998 + 423 = 11421
Step 28: 11421 + 423 = 11844
Step 29: 11844 + 423 = 12267
Step 30: 12267 + 423 = 12690
Step 31: 12690 + 423 = 13113
Step 32: 13113 + 423 = 13536
Step 33: 13536 + 423 = 13959
Step 34: 13959 + 423 = 14382
Step 35: 14382 + 423 = 14805
Step 36: 14805 + 423 = 15228
Step 37: 15228 + 423 = 15651
Step 38: 15651 + 423 = 16074
Step 39: 16074 + 423 = 16497
Step 40: 16497 + 423 = 16920
Step 41: 16920 + 423 = 17343
Step 42: 17343 + 423 = 17766
Step 43: 17766 + 423 = 18189
Step 44: 18189 + 423 = 18612
Step 45: 18612 + 423 = 19035
Step 46: 19035 + 423 = 19458
Step 47: 19458 + 423 = 19881
Step 48: 19881 + 423 = 20304
Step 49: 20304 + 423 = 20727
Step 50: 20727 + 423 = 21150
Step 51: 21150 + 423 = 21573
Step 52: 21573 + 423 = 21996
Step 53: 21996 + 423 = 22419
Step 54: 22419 + 423 = 22842
Step 55: 22842 + 423 = 23265
Step 56: 23265 + 423 = 23688
Step 57: 23688 + 423 = 24111
Step 58: 24111 + 423 = 24534
Step 59: 24534 + 423 = 24957
Step 60: 24957 + 423 = 25380
Step 61: 25380 + 423 = 25803
Step 62: 25803 + 423 = 26226
Step 63: 26226 + 423 = 26649
Step 64: 26649 + 423 = 27072
Step 65: 27072 + 423 = 27495
Step 66: 27495 + 423 = 27918
Step 67: 27918 + 423 = 28341

So, 423*67 = 28341