Small-group support
An expression can name a length. Area still multiplies lengths.
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 4. A short entry task, a model, guided examples, then a new independent try. Frames are optional.