Will it crash worksheet - error?


Really hesitant to ask this question, but it appears that the answer key has an error - either that or I have a horrible misunderstanding of the pseudocode. Probably the latter, but thanks for any help you can give!

The second and third “you try it’s” for the nested if statements look wrong.

Here’s the second one:

IF (CAN_MOVE (forward)) ----this is a “yes” so it would do the if statement
IF (CAN_MOVE (left)) -----this is a “no” since it hasn’t moved forward yet
ROTATE_LEFT () -----skip
ROTATE_RIGHT () ---------would rotate right
MOVE_FORWARD () ------would move forward
ELSE ----would skip the whole else statement
MOVE_FORWARD () -----would move forward and crash

Can I get some help with this?




Based on the answer key, I have also gotten those two examples wrong. I will continue to check on this.



Good Catch, Christine!

I remember re-working that problem a few times and must have screwed up the answers. I’ve fixed the answer key now. Take a look and verify I’m right?

Lesson learned: this stuff is hard and easy to get tripped up on!


CSP Team


Thanks, Andrea and Baker! Good example for the students, then… I mean that we all make mistakes and it is easy to get tripped up!


Hi Baker,
We just had a spirited discussion about the answer key at our LA workshop today, even after seeing that you reviewed the key two weeks ago. I told them your word was as good as gold, but they weren’t convinced.
I’m thinking we need to point teachers (and students) to the College Board documentation which defines the commands for the pseudocode. Teachers needed clarification about how the “CAN_MOVE ( )” command works. Once they have agreed on the definitions, I think they will be happy with the answer key.


Definition of CAN_MOVE() is in the purple book. I believe I just copy/pasted it into the “Will it Crash” activity.

My word is DEFINITELY NOT good as gold for the answer keys - I make mistakes all the time, and trip myself up on my own logic. Especially in cases where I re-worked certain puzzles I’m sure some mistakes linger.

If there are issues, let me know and I can fix immediately. Thanks,



Thanks, I see it in the lesson links. I’ve pasted them below. I was just kidding about having them trust your word as gold, but we do value your expertise! :slight_smile:

The link to the pseudocode documentation is here: https://docs.google.com/document/d/1i3g-wTNQ0MlCeL57SdNZ-e6QhdiKk9txfrAKTAQ4pDc

There is also a worked out example here: https://docs.google.com/document/d/1KGF-HxAP65bvQbzugKORXnzfplptWvw2eqCMntm8qS0/edit