Let's get this math done. We have 899 and we're going to multiply it by 129. This is the same as taking 899 and adding it to itself 129 times.
Step 1: 0 + 899 = 899
Step 2: 899 + 899 = 1798
Step 3: 1798 + 899 = 2697
Step 4: 2697 + 899 = 3596
Step 5: 3596 + 899 = 4495
Step 6: 4495 + 899 = 5394
Step 7: 5394 + 899 = 6293
Step 8: 6293 + 899 = 7192
Step 9: 7192 + 899 = 8091
Step 10: 8091 + 899 = 8990
Step 11: 8990 + 899 = 9889
Step 12: 9889 + 899 = 10788
Step 13: 10788 + 899 = 11687
Step 14: 11687 + 899 = 12586
Step 15: 12586 + 899 = 13485
Step 16: 13485 + 899 = 14384
Step 17: 14384 + 899 = 15283
Step 18: 15283 + 899 = 16182
Step 19: 16182 + 899 = 17081
Step 20: 17081 + 899 = 17980
Step 21: 17980 + 899 = 18879
Step 22: 18879 + 899 = 19778
Step 23: 19778 + 899 = 20677
Step 24: 20677 + 899 = 21576
Step 25: 21576 + 899 = 22475
Step 26: 22475 + 899 = 23374
Step 27: 23374 + 899 = 24273
Step 28: 24273 + 899 = 25172
Step 29: 25172 + 899 = 26071
Step 30: 26071 + 899 = 26970
Step 31: 26970 + 899 = 27869
Step 32: 27869 + 899 = 28768
Step 33: 28768 + 899 = 29667
Step 34: 29667 + 899 = 30566
Step 35: 30566 + 899 = 31465
Step 36: 31465 + 899 = 32364
Step 37: 32364 + 899 = 33263
Step 38: 33263 + 899 = 34162
Step 39: 34162 + 899 = 35061
Step 40: 35061 + 899 = 35960
Step 41: 35960 + 899 = 36859
Step 42: 36859 + 899 = 37758
Step 43: 37758 + 899 = 38657
Step 44: 38657 + 899 = 39556
Step 45: 39556 + 899 = 40455
Step 46: 40455 + 899 = 41354
Step 47: 41354 + 899 = 42253
Step 48: 42253 + 899 = 43152
Step 49: 43152 + 899 = 44051
Step 50: 44051 + 899 = 44950
Step 51: 44950 + 899 = 45849
Step 52: 45849 + 899 = 46748
Step 53: 46748 + 899 = 47647
Step 54: 47647 + 899 = 48546
Step 55: 48546 + 899 = 49445
Step 56: 49445 + 899 = 50344
Step 57: 50344 + 899 = 51243
Step 58: 51243 + 899 = 52142
Step 59: 52142 + 899 = 53041
Step 60: 53041 + 899 = 53940
Step 61: 53940 + 899 = 54839
Step 62: 54839 + 899 = 55738
Step 63: 55738 + 899 = 56637
Step 64: 56637 + 899 = 57536
Step 65: 57536 + 899 = 58435
Step 66: 58435 + 899 = 59334
Step 67: 59334 + 899 = 60233
Step 68: 60233 + 899 = 61132
Step 69: 61132 + 899 = 62031
Step 70: 62031 + 899 = 62930
Step 71: 62930 + 899 = 63829
Step 72: 63829 + 899 = 64728
Step 73: 64728 + 899 = 65627
Step 74: 65627 + 899 = 66526
Step 75: 66526 + 899 = 67425
Step 76: 67425 + 899 = 68324
Step 77: 68324 + 899 = 69223
Step 78: 69223 + 899 = 70122
Step 79: 70122 + 899 = 71021
Step 80: 71021 + 899 = 71920
Step 81: 71920 + 899 = 72819
Step 82: 72819 + 899 = 73718
Step 83: 73718 + 899 = 74617
Step 84: 74617 + 899 = 75516
Step 85: 75516 + 899 = 76415
Step 86: 76415 + 899 = 77314
Step 87: 77314 + 899 = 78213
Step 88: 78213 + 899 = 79112
Step 89: 79112 + 899 = 80011
Step 90: 80011 + 899 = 80910
Step 91: 80910 + 899 = 81809
Step 92: 81809 + 899 = 82708
Step 93: 82708 + 899 = 83607
Step 94: 83607 + 899 = 84506
Step 95: 84506 + 899 = 85405
Step 96: 85405 + 899 = 86304
Step 97: 86304 + 899 = 87203
Step 98: 87203 + 899 = 88102
Step 99: 88102 + 899 = 89001
Step 100: 89001 + 899 = 89900
Step 101: 89900 + 899 = 90799
Step 102: 90799 + 899 = 91698
Step 103: 91698 + 899 = 92597
Step 104: 92597 + 899 = 93496
Step 105: 93496 + 899 = 94395
Step 106: 94395 + 899 = 95294
Step 107: 95294 + 899 = 96193
Step 108: 96193 + 899 = 97092
Step 109: 97092 + 899 = 97991
Step 110: 97991 + 899 = 98890
Step 111: 98890 + 899 = 99789
Step 112: 99789 + 899 = 100688
Step 113: 100688 + 899 = 101587
Step 114: 101587 + 899 = 102486
Step 115: 102486 + 899 = 103385
Step 116: 103385 + 899 = 104284
Step 117: 104284 + 899 = 105183
Step 118: 105183 + 899 = 106082
Step 119: 106082 + 899 = 106981
Step 120: 106981 + 899 = 107880
Step 121: 107880 + 899 = 108779
Step 122: 108779 + 899 = 109678
Step 123: 109678 + 899 = 110577
Step 124: 110577 + 899 = 111476
Step 125: 111476 + 899 = 112375
Step 126: 112375 + 899 = 113274
Step 127: 113274 + 899 = 114173
Step 128: 114173 + 899 = 115072
Step 129: 115072 + 899 = 115971

So, 899*129 = 115971