## IM Commentary

This tasks gives a verbal description for computing the perimeter of a rectangle and asks the students to find an expression for this perimeter. They then have to use the expression to evaluate the perimeter for specific values of the two variables. In this problem, the variable names $l$ and $w$ convey the meaning of length and width of a rectangle. A follow up to this task is Rectangle Perimeter 2, where students are asked to determine if expressions for the perimeter of a rectangle are correct and equivalent.