for an "easy" but "long" way of doing it, just go through the multiplication of 5 starting from 10. 10 x 5 is 50. 50 is less than 85 so you can go up a couple numbers and do 15 x 5 which is 75. 75 is a little closer so do 16 x 5 which is 80. Thats super close but not quite the answer you are looking for. So, do one more: 17 x 5 which is 85. There fore, 17 is your answer. Unless you know how to do long division. then you do long division which would end in the answer being 17.
