Samuel Otten catalogs different responses to the "when will I ever use this?" question and points out their shortcomings:
I believe that thinking and acting as if the justification for teaching and learning mathematics is found solely in everyday applications can be dangerous. Mathematics does not exist only to serve other professions, nor is it merely a collection of algorithms and procedures for dealing with real-world situations. Such a mind-set essentially paints our discipline into a weak and lonely corner and leaves undefended many of its greatest aspects.
A fantastic piece and a quick read. His closing recommendation is dead on. When kids students ask that question, they aren't really asking that question, right?
Not yet sure what to think. I’m trying to remember when I was 12 how I would react to http://weusemath.org. How would your students react?
2012 Aug 28. Damon Hedman offers a great example of the teacher getting cornered by the real world:
Student: When am I ever going to use this?
Hedman: [mentions a gazillion real life uses]
Student: But those don’t apply to me!
Hedman: [bangs head against the wall]
No one wins at that game.