A quick idea on why having to show your work is an important skill; not sure how accurate it is, so I'd love feedback. If you want to be a computer programmer, don't you have to know how to translate a "word problem" into mathematical terms? Even if you intuitively know that Susie will have 7 apples after her friend gives her 4 more, computers are dumb devices that don't know this stuff. It seems to be that being able to show your work would be necessary for programming.
I realize not every kid is going to grow up to be a programmer, but at the elementary level, who can say?
