I wonder, ColinsMum, was your percent problem a part of a bigger problem? I ask because my dd can do the work she has "forgotten" if it is part of a more difficult problem. So for example, if you gave her a fraction problem or a percent problem, she is likely to get it wrong, and get upset that it is too hard. But, if you give her a problem that requires her to know 40% of 10 in the process of getting to a solution to a bigger problem, she's got no problem with it. Do you think this is what happened to your students?
Absolutely - sorry, I thought I'd been clear about that! I had no interest in testing my students' abilities to do percentages; it was just an accidental part of testing them on something else. Yes, I'm sure this was an important aspect of what happened - but I was still shocked!
