Identify the odd item: Three are basic stationery tools for writing/erasing (Pencil, Eraser, Sharpener). One is an electronic computation device. Choose the outlier.

Introduction / Context:
Object classification can hinge on function and technology (manual vs electronic).

Given Data / Assumptions:

• Pencil → writing implement.
• Eraser → removes pencil marks.
• Sharpener → maintains pencil point.
• Calculator → electronic computation device.

Concept / Approach:
Group by function: three form a writing kit; one is a separate electronic tool.

Step-by-Step Solution:

Verification / Alternative check:
Ask which item requires power/electronics; only the Calculator does.

Why Other Options Are Wrong:
They are functionally integrated with writing by pencil.

Common Pitfalls:
Treating all as “school items” without considering functional grouping.

Final Answer:
Calculator is the odd item.