OK, let's work through this together. We're starting with 336 and we're going to multiply it by 124, which means we add 336 to itself 124 times.
Step 1: 0 + 336 = 336
Step 2: 336 + 336 = 672
Step 3: 672 + 336 = 1008
Step 4: 1008 + 336 = 1344
Step 5: 1344 + 336 = 1680
Step 6: 1680 + 336 = 2016
Step 7: 2016 + 336 = 2352
Step 8: 2352 + 336 = 2688
Step 9: 2688 + 336 = 3024
Step 10: 3024 + 336 = 3360
Step 11: 3360 + 336 = 3696
Step 12: 3696 + 336 = 4032
Step 13: 4032 + 336 = 4368
Step 14: 4368 + 336 = 4704
Step 15: 4704 + 336 = 5040
Step 16: 5040 + 336 = 5376
Step 17: 5376 + 336 = 5712
Step 18: 5712 + 336 = 6048
Step 19: 6048 + 336 = 6384
Step 20: 6384 + 336 = 6720
Step 21: 6720 + 336 = 7056
Step 22: 7056 + 336 = 7392
Step 23: 7392 + 336 = 7728
Step 24: 7728 + 336 = 8064
Step 25: 8064 + 336 = 8400
Step 26: 8400 + 336 = 8736
Step 27: 8736 + 336 = 9072
Step 28: 9072 + 336 = 9408
Step 29: 9408 + 336 = 9744
Step 30: 9744 + 336 = 10080
Step 31: 10080 + 336 = 10416
Step 32: 10416 + 336 = 10752
Step 33: 10752 + 336 = 11088
Step 34: 11088 + 336 = 11424
Step 35: 11424 + 336 = 11760
Step 36: 11760 + 336 = 12096
Step 37: 12096 + 336 = 12432
Step 38: 12432 + 336 = 12768
Step 39: 12768 + 336 = 13104
Step 40: 13104 + 336 = 13440
Step 41: 13440 + 336 = 13776
Step 42: 13776 + 336 = 14112
Step 43: 14112 + 336 = 14448
Step 44: 14448 + 336 = 14784
Step 45: 14784 + 336 = 15120
Step 46: 15120 + 336 = 15456
Step 47: 15456 + 336 = 15792
Step 48: 15792 + 336 = 16128
Step 49: 16128 + 336 = 16464
Step 50: 16464 + 336 = 16800
Step 51: 16800 + 336 = 17136
Step 52: 17136 + 336 = 17472
Step 53: 17472 + 336 = 17808
Step 54: 17808 + 336 = 18144
Step 55: 18144 + 336 = 18480
Step 56: 18480 + 336 = 18816
Step 57: 18816 + 336 = 19152
Step 58: 19152 + 336 = 19488
Step 59: 19488 + 336 = 19824
Step 60: 19824 + 336 = 20160
Step 61: 20160 + 336 = 20496
Step 62: 20496 + 336 = 20832
Step 63: 20832 + 336 = 21168
Step 64: 21168 + 336 = 21504
Step 65: 21504 + 336 = 21840
Step 66: 21840 + 336 = 22176
Step 67: 22176 + 336 = 22512
Step 68: 22512 + 336 = 22848
Step 69: 22848 + 336 = 23184
Step 70: 23184 + 336 = 23520
Step 71: 23520 + 336 = 23856
Step 72: 23856 + 336 = 24192
Step 73: 24192 + 336 = 24528
Step 74: 24528 + 336 = 24864
Step 75: 24864 + 336 = 25200
Step 76: 25200 + 336 = 25536
Step 77: 25536 + 336 = 25872
Step 78: 25872 + 336 = 26208
Step 79: 26208 + 336 = 26544
Step 80: 26544 + 336 = 26880
Step 81: 26880 + 336 = 27216
Step 82: 27216 + 336 = 27552
Step 83: 27552 + 336 = 27888
Step 84: 27888 + 336 = 28224
Step 85: 28224 + 336 = 28560
Step 86: 28560 + 336 = 28896
Step 87: 28896 + 336 = 29232
Step 88: 29232 + 336 = 29568
Step 89: 29568 + 336 = 29904
Step 90: 29904 + 336 = 30240
Step 91: 30240 + 336 = 30576
Step 92: 30576 + 336 = 30912
Step 93: 30912 + 336 = 31248
Step 94: 31248 + 336 = 31584
Step 95: 31584 + 336 = 31920
Step 96: 31920 + 336 = 32256
Step 97: 32256 + 336 = 32592
Step 98: 32592 + 336 = 32928
Step 99: 32928 + 336 = 33264
Step 100: 33264 + 336 = 33600
Step 101: 33600 + 336 = 33936
Step 102: 33936 + 336 = 34272
Step 103: 34272 + 336 = 34608
Step 104: 34608 + 336 = 34944
Step 105: 34944 + 336 = 35280
Step 106: 35280 + 336 = 35616
Step 107: 35616 + 336 = 35952
Step 108: 35952 + 336 = 36288
Step 109: 36288 + 336 = 36624
Step 110: 36624 + 336 = 36960
Step 111: 36960 + 336 = 37296
Step 112: 37296 + 336 = 37632
Step 113: 37632 + 336 = 37968
Step 114: 37968 + 336 = 38304
Step 115: 38304 + 336 = 38640
Step 116: 38640 + 336 = 38976
Step 117: 38976 + 336 = 39312
Step 118: 39312 + 336 = 39648
Step 119: 39648 + 336 = 39984
Step 120: 39984 + 336 = 40320
Step 121: 40320 + 336 = 40656
Step 122: 40656 + 336 = 40992
Step 123: 40992 + 336 = 41328
Step 124: 41328 + 336 = 41664

So, 336*124 = 41664