Sophia asked the students in her class to name their favorite sports. she made a list to display the results. 1/3 of students name basketball. 1/8 of students named soccer. 5/12 of students named football. the rest of the students in the class named baseball. what fraction of the students in the class named baseball as their favorite sport?

Let's add up all of the other sports except baseball (which we don't know)
1/3 + 1/8 + 5/12   Common denominator is 24 so let change them to 24ths

8/24 + 3/24 + 10/24 = 21/24   Since all the sport put together can be represented by the number 1, we will do 1 - 21/24
Instead of 1, I will use 24/24 (which means 1)     

24/24 - 21/24 = 3/24  or 1/8 reduced.   1/8 of the student named baseball as their favorite sport.