6.91, 7, 7 1/8, 15/2 OR 7 1/2
6.91 would be the least due to the whole number (6) being already less than 7. Next is 7 because of it being by itself with no fraction added. Next is 7 1/8 and 15/2. 15/2 is greater than 7 1/8 because when simplified you get 7 1/2 which can become 7 4/8, therefore greater than 7 1/8.
