This activity is a 20 question test prep activity for the Math 1 or Algebra 1 end of course exam. The 20 questions are mixed review multiple choice questions that are end of course type questions. In the directions, the students will find a link to a website that is a mystery piano secret message decoder. The students will work to solve all 20 problems. Each correct multiple choice answer corresponds with a piano key on the mystery piano secret message decoder website. If the students play the correct 20 piano keys in order, then it will give them a secret message. If the students do not play a correct piano key, then it will start them over again. The piano keys also physically turn red or green based on whether they are getting them correct or not. This website helps the students self-check their work because they will not be able to get the secret message until they get all 20 problems correct. The secret message is a question, and the students have space on the worksheet to write their answer to the secret message. If you want to do this activity without the technology component, then I have also included a regular multiple choice worksheet version of the 20 questions. The answer key is included and it is the same for both versions.