One of the difficulties in teaching order of  operations to students is that one of the most often used shortcuts actually causes student confusion.  Most students know that they should use PEMDAS when deciding what math operation to do first.  The problem with PEMDAS is that often students think that multiplication has to come before division and addition before subtraction. Instead, teach students to think of the operations as "levels." Just like on an elevator, you have to do one level before you can get to the next.  Be sure to start at the bottom - just like the first floor of a building. 

Lesson Plan #1: Panhandle Circle-square: Geometry and Real-world Applications Using “Panhandle Circle-square” project at http://tomrchambers.com/circle_square.html and other locations via Google Earth to study Geometry and make mathematical calculations as they relate to real world applications such as the farmers in the Texas Panhandle using square plots of land and circular irrigation of their crops to make a living. Their geometrical calculations are precise to be efficient with their livelihood

Lesson Plan #2: Geometric Concepts In this lesson, students define geometry terms and then take photos of geometric figures that illustrate examples of their use in the real world.

Lesson Plan #3: Graph Plotting