These Math Puzzles are a bit more difficult than those found in Sets 1 & 2. They include "order of operations", negative numbers, and basic algebra. They are great for a Pre-algebra or Algebra 1 classroom. I like to have one projected on the board at the start of class and let the students work on it and debate their answers before class begins. At the start of class we go over the solution (given on the next slide). This gets the kids engaged in math before the class even starts. They could also be used for "bonus" questions on quizzes or homework. Math puzzles are all over the internet but these are carefully selected, have the solutions, and are ready to project using powerpoint. Of course they can be used year after year.