This lesson is the 5th in a series of 5 lessons focusing on solving equations. The lesson contains a student worksheet and a teacher (TE) file. The teacher file matches the student worksheet and provides instructions and answers, shown in red text. The lessons instructs students to "undo" what is being done to the variable in order to solve the equation (isolate the variable). The lesson uses the 'number tricks' idea introduced in the first lesson. This lesson is well organized and can easily be used in a classroom setting.