OK, let's work through this together. We're starting with 424 and we're going to multiply it by 126, which means we add 424 to itself 126 times.
Step 1: 0 + 424 = 424
Step 2: 424 + 424 = 848
Step 3: 848 + 424 = 1272
Step 4: 1272 + 424 = 1696
Step 5: 1696 + 424 = 2120
Step 6: 2120 + 424 = 2544
Step 7: 2544 + 424 = 2968
Step 8: 2968 + 424 = 3392
Step 9: 3392 + 424 = 3816
Step 10: 3816 + 424 = 4240
Step 11: 4240 + 424 = 4664
Step 12: 4664 + 424 = 5088
Step 13: 5088 + 424 = 5512
Step 14: 5512 + 424 = 5936
Step 15: 5936 + 424 = 6360
Step 16: 6360 + 424 = 6784
Step 17: 6784 + 424 = 7208
Step 18: 7208 + 424 = 7632
Step 19: 7632 + 424 = 8056
Step 20: 8056 + 424 = 8480
Step 21: 8480 + 424 = 8904
Step 22: 8904 + 424 = 9328
Step 23: 9328 + 424 = 9752
Step 24: 9752 + 424 = 10176
Step 25: 10176 + 424 = 10600
Step 26: 10600 + 424 = 11024
Step 27: 11024 + 424 = 11448
Step 28: 11448 + 424 = 11872
Step 29: 11872 + 424 = 12296
Step 30: 12296 + 424 = 12720
Step 31: 12720 + 424 = 13144
Step 32: 13144 + 424 = 13568
Step 33: 13568 + 424 = 13992
Step 34: 13992 + 424 = 14416
Step 35: 14416 + 424 = 14840
Step 36: 14840 + 424 = 15264
Step 37: 15264 + 424 = 15688
Step 38: 15688 + 424 = 16112
Step 39: 16112 + 424 = 16536
Step 40: 16536 + 424 = 16960
Step 41: 16960 + 424 = 17384
Step 42: 17384 + 424 = 17808
Step 43: 17808 + 424 = 18232
Step 44: 18232 + 424 = 18656
Step 45: 18656 + 424 = 19080
Step 46: 19080 + 424 = 19504
Step 47: 19504 + 424 = 19928
Step 48: 19928 + 424 = 20352
Step 49: 20352 + 424 = 20776
Step 50: 20776 + 424 = 21200
Step 51: 21200 + 424 = 21624
Step 52: 21624 + 424 = 22048
Step 53: 22048 + 424 = 22472
Step 54: 22472 + 424 = 22896
Step 55: 22896 + 424 = 23320
Step 56: 23320 + 424 = 23744
Step 57: 23744 + 424 = 24168
Step 58: 24168 + 424 = 24592
Step 59: 24592 + 424 = 25016
Step 60: 25016 + 424 = 25440
Step 61: 25440 + 424 = 25864
Step 62: 25864 + 424 = 26288
Step 63: 26288 + 424 = 26712
Step 64: 26712 + 424 = 27136
Step 65: 27136 + 424 = 27560
Step 66: 27560 + 424 = 27984
Step 67: 27984 + 424 = 28408
Step 68: 28408 + 424 = 28832
Step 69: 28832 + 424 = 29256
Step 70: 29256 + 424 = 29680
Step 71: 29680 + 424 = 30104
Step 72: 30104 + 424 = 30528
Step 73: 30528 + 424 = 30952
Step 74: 30952 + 424 = 31376
Step 75: 31376 + 424 = 31800
Step 76: 31800 + 424 = 32224
Step 77: 32224 + 424 = 32648
Step 78: 32648 + 424 = 33072
Step 79: 33072 + 424 = 33496
Step 80: 33496 + 424 = 33920
Step 81: 33920 + 424 = 34344
Step 82: 34344 + 424 = 34768
Step 83: 34768 + 424 = 35192
Step 84: 35192 + 424 = 35616
Step 85: 35616 + 424 = 36040
Step 86: 36040 + 424 = 36464
Step 87: 36464 + 424 = 36888
Step 88: 36888 + 424 = 37312
Step 89: 37312 + 424 = 37736
Step 90: 37736 + 424 = 38160
Step 91: 38160 + 424 = 38584
Step 92: 38584 + 424 = 39008
Step 93: 39008 + 424 = 39432
Step 94: 39432 + 424 = 39856
Step 95: 39856 + 424 = 40280
Step 96: 40280 + 424 = 40704
Step 97: 40704 + 424 = 41128
Step 98: 41128 + 424 = 41552
Step 99: 41552 + 424 = 41976
Step 100: 41976 + 424 = 42400
Step 101: 42400 + 424 = 42824
Step 102: 42824 + 424 = 43248
Step 103: 43248 + 424 = 43672
Step 104: 43672 + 424 = 44096
Step 105: 44096 + 424 = 44520
Step 106: 44520 + 424 = 44944
Step 107: 44944 + 424 = 45368
Step 108: 45368 + 424 = 45792
Step 109: 45792 + 424 = 46216
Step 110: 46216 + 424 = 46640
Step 111: 46640 + 424 = 47064
Step 112: 47064 + 424 = 47488
Step 113: 47488 + 424 = 47912
Step 114: 47912 + 424 = 48336
Step 115: 48336 + 424 = 48760
Step 116: 48760 + 424 = 49184
Step 117: 49184 + 424 = 49608
Step 118: 49608 + 424 = 50032
Step 119: 50032 + 424 = 50456
Step 120: 50456 + 424 = 50880
Step 121: 50880 + 424 = 51304
Step 122: 51304 + 424 = 51728
Step 123: 51728 + 424 = 52152
Step 124: 52152 + 424 = 52576
Step 125: 52576 + 424 = 53000
Step 126: 53000 + 424 = 53424

So, 424*126 = 53424