Answer:
it is 1/4, since if you subtract 1/3 from 1/4, and then add 1/3 again, it will stay as 1/4. But since that is a bit complicated, its because 1/3 and -1/3 cancels out.
if you don't get it, here is why.
1/4 - 1/3 + 1/3
that is the equation right? so lets ignore the 1/4. for now. so then it is just
- 1/3 + 1/3. -1/3 plus 1/3 is zero. so now we add back the 1/4. 1/4 + 0 is just 1/4.
I hope this helps, if you need more help i'll gladly explain it! :)