Family practice
An expression can name a length. Area still multiplies lengths.
Optional until a teacher marks it
A rectangle is (x + 2) by 4. x = 3.
Area is the product of two perpendicular side lengths. An expression can name a side, but it must be evaluated or multiplied as a length, not added into the other side.
Problem 1 of 8. What we learned, an example, a few together, then independent practice.