Feature Request: Add Fraction Display Mode to Windows Calculator

[Aryan-Purohit]

Problem Statement

Many students, educators, engineers, and hobbyists frequently work with fractions, not just decimals. Windows Calculator currently converts all results into decimal form, which makes it difficult to:

• Verify steps in math homework
• Work with rational numbers in exact form
• Avoid rounding errors in engineering or scientific calculations
• Compare fractional values without manually converting back

This creates friction for users who need exact arithmetic, not approximations.

Evidence or User Insights

• Competing calculators (TI, Casio, HP, macOS Calculator) support fraction display.
• Many GitHub issues and Feedback Hub posts request exact rational output.
• Fraction support is a common expectation in educational tools.
• Users working with repeating decimals (e.g., 0.3333…) often want the exact fraction (1/3).

Fraction display is a widely requested and pedagogically important feature.

Proposal

Add an optional Fraction Mode that allows users to view results as simplified fractions.

Key behaviors:

• Display results as a/b when the value is rational.
• Automatically simplify fractions (e.g., 8/12 → 2/3).
• Allow toggling between Decimal ↔ Fraction via a button or settings toggle.
• Support mixed numbers (e.g., 7/4 → 1 3/4) as an optional view.
• Support converting repeating decimals to fractions when possible.
• Maintain full compatibility with existing decimal workflows.

Technical feasibility:

• The CalcManager engine already handles high‑precision rational arithmetic internally.
• A fraction‑formatting layer could be added without altering core computation logic.
• UI changes would be minimal (a toggle + display formatting).

Goals

• User can view exact rational results instead of rounded decimals.
• User can toggle between decimal and fraction formats.
• User can avoid rounding errors in educational and engineering contexts.

Non-Goals

• Not adding symbolic algebra (e.g., factoring, solving equations).
• Not changing the underlying computation engine.
• Not implementing step‑by‑step fraction simplification (unless requested later).

Low-Fidelity Concept

Example:

• Input: 0.75 → Output: 3/4
• Input: 1 ÷ 3 → Output: 1/3
• Input: 7 ÷ 4 → Output: 7/4 (or 1 3/4 if mixed mode enabled)

[ Fraction Mode: ON ]
Result: 5/8

Requested Assignment

I would like to implement this feature if approved.

[Aryan-Purohit]

Thanks for raising that. Yes, I have considered the edge cases. For division-by-zero, it wouldn't attempt conversion and point towards the existing error case "Cannot divide by zero". For other edge cases:

• Non-Finite Results (∞, −∞, NaN): Skip fraction formatting and give the existing output behavior.
• Very large integers or results out of safe rational range: Fall back to decimal to avoid overflow or performance issues.
• Repeating decimals that cannot be reliably detected: Return the decimal result rather than guessing the incorrect result.

I am also thinking of adding a toggle, just like the degree/radian one in the scientific calculator screen, so that it naturally fits with the existing UI. What do you think?