It appears that the Key and the Master document are the same.
Here’s the key: https://studio.code.org/s/cspoptional/stage/7/puzzle/1
Here’s the sheet for the kids: https://docs.google.com/document/d/1luezxRb3SeHnehy32SB_keXboZktutVG4RB3JNvW2r4/edit
If I’m just looking in the wrong places (the lesson is here - https://curriculum.code.org/csp/unit4/6/optional/2/), please let me know where the real key is.
Otherwise, I’ll post my own answers.