Fun educational activity where children identify and color rectangular objects like notebooks and juice boxes.

To solve this problem, we need to find all the shapes that are rectangles. A rectangle is a four-sided shape with four right angles (square corners). The opposite sides are equal in length.

Let's look at each item one by one:

1. Notebook:
* The main cover of the notebook is a large rectangle.
* There is also a smaller rectangular label on the front cover.
* Action: Color the large outer shape and the small inner label.

2. Juice Box:
* The main body of the juice box is a rectangle (even though it's tilted).
* The picture frame on the front containing the fruit slices is also a rectangle.
* Action: Color the main body of the box and the inner picture frame. (Do not color the straw or the fruit slices).

3. Envelope:
* The outer boundary of the envelope forms a rectangle.
* The triangular flaps inside are triangles, not rectangles.
* Action: Color only the outer rectangular border/shape.

4. Crayons Box:
* The main box holding the crayons is a large rectangle.
* The handle tab on top is a smaller rectangle.
* The window showing the crayon tips is a rectangle.
* The individual crayon bodies visible in the window are small rectangles.
* Action: Color the main box, the handle tab, the window frame, and the small rectangular bodies of the crayons inside the window.

Summary of what to color:
* Notebook: The big cover and the small name tag.
* Juice: The box itself and the square/rectangular picture on it.
* Envelope: The outside shape only.
* Crayons: The box, the handle, the window, and the crayon sticks inside.

Final Answer:
You should color the following rectangular parts:
1. Notebook: The entire outer cover and the small rectangular label on the front.
2. Juice Box: The main body of the carton and the rectangular frame around the fruit picture.
3. Envelope: The outer rectangular shape of the envelope.
4. Crayons: The main box, the small handle tab on top, the rectangular window, and the small rectangular bodies of the crayons seen inside the window.