Students solve two digit plus one digit addition and subtraction problems to find the secret Halloween message. This helps with common core standard CCSS.Math.Content.2.NBT.B.5: "Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction." A teacher key is included with the student problems and the secret message which is Trick or Treat. Explain to students that they need to find the answer to the math problem then see if that number is on the secret message. If it is write the letter that goes along with that number on the line above it. Do the first few problems with the students until they get the hang of it. This is a good activity to do in math stations and something that students can complete independently once they understand how to do it. My second grade students loved this they were very excited to find the answer to the secret message.