This worksheet allows advanced students to apply their knowledge of two-step equations to find incorrect steps and further their own understanding. Students may find mistakes in any step of the work shown. They are asked to circle the incorrect portion, make corrections, and find the correct solution. The second page requires students to experiment with equations in order to find how characters in the worksheet got their solutions.
I have personally used this in my classroom to introduce a game for the following class in which students made mistakes on purpose to "trick" their classmates.
I hope you and your students enjoy this activity!