I found a new way to "encourage" my girls when they complain about having to learn diagramming sentences or working out geometry proofs. "I will NEVER need to do this in real life when I'm an adult," they tell me.
I agree with them actually. I've been an adult for a number of years and not once have my skills in diagramming sentences come in handy. Nor has anyone ever burst into my office (back when I worked outside the home) and said, "Quick! Tell me! Is this an appositive or a predicate nominative?"
Nevertheless, they do have to learn this stuff now because the department of education says so - although I hear they are now dropping cursive as a necessary skill in life so there goes all that time I spent battling with the kids teaching them that.
Anyway, now when they complain about having to learn something they find unnecessary to their future lives I just pull up this picture on the the computer and point to it.
"That could just be her grandfather," they say to me.
"Look where his right hand is," I respond.
"Ew," they say.
"Get back to work," I tell them.
And they jump back to their work with great enthusiasm........for at least an hour.