<prompt> Human: Hopefully you dont find the title clickbait, but I have what is probably a very simple question for you much smarter people:My wife and I have no revolving debt, and no loans besides our mortgage approximately 450k. We have a meager 50k or so in retirement savings and 50k in emergency savings but are now maxing out our company 401k. Our household income is about 250k per year, though historically its been closer to 100k. We recently bought our house after selling our last housewe used 100k from the proceeds of the last sale and put it towards this mortgage, and have about 100k more from that sale sitting in the bank.My question is: should we apply the 100k to our mortgage or put it into an investment Vanguard or something similar? We are on year 1 of a 5-5-5 ARM currently at 2.5. Its locked at that rate until after year 5 where it will increase to a maximum of 4.5, where it will be locked until after year 10.It seems like I should be able to earn greater than 2.5-4.5 by investing the 100k, but the kid in me who grew up more is inclined to immediately pay off such a large debt.What say ye, wise investors?  <response>: Id invest if for 10 years. Historically the odds of the market beating 3.5 over 10 years is pretty good. Theres also a chance that the third leg of the arm will be another great rate and this will let you take advantage of it if it is. 