OK, let's crack this. We're given 899 and our task is to multiply it by 42. Essentially, we'll be adding 899 to itself 42 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

So, 899*42 = 37758