Question: What do they call an alligator that sneaks up and bites you from the back? Answer: A tailgator. Get it..."tailgater".
You can also check the answer using simplified algebraic expressions here.
Algebra is not high on the list of most people's favorite things to do, so creative teachers use pizzazz to make this subject fun. They make puzzles that are designed so that students will construct a joke or unscramble the answer to a riddle in the process of checking their answers.
Of interest, the new math app from BinaryLabs, Dexteria Dots, has been named the Best New App in Education by Apple, and is being featured on the App Store. Find out more here.