About This Lesson
The document is revised base on the Cat Food by Mathematic Assessment 2009. The bottom of the first page of this revised document contained with the link. Teachers also can google "Cat Food by Mathematic Assessment 2009" to see original document (on page 3 of its pdf file) if you do not want to click the link on my document. The idea: Proportion extend to Rational Expression which can conver to another form of linear equaiton in embeded concept of direct variation. We may elaborate to decide how we want to approach according to the grade level of our students
