The issue I had with in the EPGY course my DD did was that it was not always clear (even to me) from the problem on the screen what was supposed to go in the empty box. It wasn't getting the answer that was the issue, but that they had a particular (but not yet taught) desired intermediate step, and the empty boxes were in the intermediate step.
Aaaah, I see. So maybe someone designed the pegagogy, and someone else designed the input form, but the two things didn't marry up...
Have to say, boxes like those W'sMama describe would make me want to throw the computer across the room. So sympathy.
