<prompt> Human: My husband and I just got a new house 170k, but we also have student loan debt 80k with different interest rates from 1.5-9. Our mortgage interest rate is 4 for a 15-year mortgage. At what point would it be smarter to put extra money on our mortgage versus student loans. Based on the avalanche method, we should pay down the highest interest loans, but does there come a point where the lower interest mortgage accumulates more in interest since the loan itself is larger than higher rate student loans each with an overall lower principle?  <response>: The size of the loan does not matter, only the rate matters.Always pay down the highest rate loan first regardless of the balance in order to pay the least amount of money in interest. 