Well, we've discussed it. The general consensus is that most of the time this is a losing battle until kids are doing more advanced mathematics. Through algebra and in some cases a lot of high school geometry, your average EG/PG person simply doesn't need to write each step out, if they have the working memory capacity not to.
Until they see some real dis-incentive for not doing so, nothing much WILL convince them. We're hoping that calculus will supply the necessary motivation, because thus far, only physics has been sufficient inducement for our DD.
She really can do matrix algebra steps in her head that neither her dad nor I can. She's just not like most people.
How on earth to convince her that she "must" show those steps?
Uhhh-- we don't. She's proven that she simply doesn't NEED to. Why make her do something that she has mastery of, and doesn't need to do for herself?
We have finally moved into a phase where she sees her own limitations better in this respect, and has the ability to self-check, and -- where she is in error-- correct by reducing steps done in her head on the next iteration.
Tutoring other more typical students has helped her to understand what OTHERS need to see to "follow" her work. But I still wouldn't say that she is "good" about it without someone actually asking her "Hey-- wait a minute-- how did you get THAT?"
