Sure thing! We've got 401 and we're gonna multiply it by 99. That's the same as adding 401 to itself 99 times.
Step 1: 0 + 401 = 401
Step 2: 401 + 401 = 802
Step 3: 802 + 401 = 1203
Step 4: 1203 + 401 = 1604
Step 5: 1604 + 401 = 2005
Step 6: 2005 + 401 = 2406
Step 7: 2406 + 401 = 2807
Step 8: 2807 + 401 = 3208
Step 9: 3208 + 401 = 3609
Step 10: 3609 + 401 = 4010
Step 11: 4010 + 401 = 4411
Step 12: 4411 + 401 = 4812
Step 13: 4812 + 401 = 5213
Step 14: 5213 + 401 = 5614
Step 15: 5614 + 401 = 6015
Step 16: 6015 + 401 = 6416
Step 17: 6416 + 401 = 6817
Step 18: 6817 + 401 = 7218
Step 19: 7218 + 401 = 7619
Step 20: 7619 + 401 = 8020
Step 21: 8020 + 401 = 8421
Step 22: 8421 + 401 = 8822
Step 23: 8822 + 401 = 9223
Step 24: 9223 + 401 = 9624
Step 25: 9624 + 401 = 10025
Step 26: 10025 + 401 = 10426
Step 27: 10426 + 401 = 10827
Step 28: 10827 + 401 = 11228
Step 29: 11228 + 401 = 11629
Step 30: 11629 + 401 = 12030
Step 31: 12030 + 401 = 12431
Step 32: 12431 + 401 = 12832
Step 33: 12832 + 401 = 13233
Step 34: 13233 + 401 = 13634
Step 35: 13634 + 401 = 14035
Step 36: 14035 + 401 = 14436
Step 37: 14436 + 401 = 14837
Step 38: 14837 + 401 = 15238
Step 39: 15238 + 401 = 15639
Step 40: 15639 + 401 = 16040
Step 41: 16040 + 401 = 16441
Step 42: 16441 + 401 = 16842
Step 43: 16842 + 401 = 17243
Step 44: 17243 + 401 = 17644
Step 45: 17644 + 401 = 18045
Step 46: 18045 + 401 = 18446
Step 47: 18446 + 401 = 18847
Step 48: 18847 + 401 = 19248
Step 49: 19248 + 401 = 19649
Step 50: 19649 + 401 = 20050
Step 51: 20050 + 401 = 20451
Step 52: 20451 + 401 = 20852
Step 53: 20852 + 401 = 21253
Step 54: 21253 + 401 = 21654
Step 55: 21654 + 401 = 22055
Step 56: 22055 + 401 = 22456
Step 57: 22456 + 401 = 22857
Step 58: 22857 + 401 = 23258
Step 59: 23258 + 401 = 23659
Step 60: 23659 + 401 = 24060
Step 61: 24060 + 401 = 24461
Step 62: 24461 + 401 = 24862
Step 63: 24862 + 401 = 25263
Step 64: 25263 + 401 = 25664
Step 65: 25664 + 401 = 26065
Step 66: 26065 + 401 = 26466
Step 67: 26466 + 401 = 26867
Step 68: 26867 + 401 = 27268
Step 69: 27268 + 401 = 27669
Step 70: 27669 + 401 = 28070
Step 71: 28070 + 401 = 28471
Step 72: 28471 + 401 = 28872
Step 73: 28872 + 401 = 29273
Step 74: 29273 + 401 = 29674
Step 75: 29674 + 401 = 30075
Step 76: 30075 + 401 = 30476
Step 77: 30476 + 401 = 30877
Step 78: 30877 + 401 = 31278
Step 79: 31278 + 401 = 31679
Step 80: 31679 + 401 = 32080
Step 81: 32080 + 401 = 32481
Step 82: 32481 + 401 = 32882
Step 83: 32882 + 401 = 33283
Step 84: 33283 + 401 = 33684
Step 85: 33684 + 401 = 34085
Step 86: 34085 + 401 = 34486
Step 87: 34486 + 401 = 34887
Step 88: 34887 + 401 = 35288
Step 89: 35288 + 401 = 35689
Step 90: 35689 + 401 = 36090
Step 91: 36090 + 401 = 36491
Step 92: 36491 + 401 = 36892
Step 93: 36892 + 401 = 37293
Step 94: 37293 + 401 = 37694
Step 95: 37694 + 401 = 38095
Step 96: 38095 + 401 = 38496
Step 97: 38496 + 401 = 38897
Step 98: 38897 + 401 = 39298
Step 99: 39298 + 401 = 39699

So, 401*99 = 39699