There are 16 students in the school play. one fourth of the students are wearing yellow costumes. six students are wearing purple costumes. the remaining students are wearing orange costumes. how many students wearing orange costumes?

There are 16 students total.
1/4 (4 students)--> Yellow Costumes
6 students--> Purple Costumes
(?) students--> Orange Costumes.

We know that one fourth of the students is 4 students by doing simple division.
6 students are wearing purple costumes. 
Add these together.
4+6 = 10

The remaining students are wearing orange costumes.
There are 6 students remaining.
Therefore, 6 students are wearing orange costumes.

6 Students

4 wearing Yellow

6 wearing purple

6 wearing orange

6 plus 4= 10 plus 6= 16

hope this helps :)