In a classroom, 1/6 of the students are wearing blue shirts and 2/3 are wearing white shirts. there are 36 students in the class. how many students are wearing a shirt other than blue or white?

The best thing to do here is to find out what one part is equal too, add these up and then subtract it from the original number.
As 1/6 of the students are wearing blue shirts, you need to find out what 1/6 is. 
As there are 36 students, you need to divide this by 6 to get one part.
36/6=6
Therefore, there are six students wearing blue shirts.
As there are 2/3 students wearing white shirts, you need to find out what 2/3 of 36 is. 
The best thing to do is to find 1/3 then double it.
To do this, divide 36 by 3.
36/3= 12
12*2= 24
Therefore, there are 24 students wearing white shirts.
As you're looking for the students that aren't wearing blue and white, you need to add the total together, and then subtract this from 36.
6+24=30
36-30= 6
Therefore, there are 6 students that are wearing shirts that aren't blue or white.
Hope this helps :)