Khan/khan-exercises — pull request #47788 by petercollingridge (2013-06-12 21:56:54+00:00)
Title: Add new exercise type and improve hints

Add exercise type which just shows an equation. Improve hints and generally tidy up.
For Trello card: https://trello.com/card/even-and-odd-functions/5166dc745b4dc7926c000a71/56