Calculator

A browser-based math calculator built with React, TypeScript, and mathjs. Before you calculate, you choose how results are presented; afterward you get step-by-step or immediate answers, a persistent history, and expressive “continue from last result” behaviour using ANS.

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Features

Modes

On first launch you pick one mode (you can switch later):

• Step-by-step guide — Walks through intermediate simplifications for supported numeric expressions (order of operations, functions, etc.).
• Immediate result — Computes the answer without showing the breakdown.

Both modes parse the same expression language.

Expressions

• Arithmetic, parentheses, powers (^), and common functions (e.g. sqrt, sin, cos, tan, log, abs, …).
• Built-in constants pi and e (and related mathjs literals where applicable).

Last answer and ANS

After a successful calculation (no error, non-empty result):

• The expression field is cleared; the numeric result is stored as the last answer.
• Typing +, *, /, or ^ at the start of a new line (with an existing last answer) automatically inserts ANS so you see e.g. ANS+ …, ANS* ….
• Leading negative numbers like -7 become ANS-7 when a last answer exists (binary subtraction from that answer).

Ans button: inserts the token ANS at the cursor (enabled when there is a last answer).

Underlying evaluation replaces each ANS with the stored value before mathjs runs, so chaining is predictable. A hint line shows the expanded expression when ANS is present.

History

Completed runs are listed in reverse chronological order (newest first), with:

• Expression as entered (including ANS when applicable),
• Evaluated as when substitution was applied,
• Outcome (result or error message),
• Timestamp,
• Solve mode (Steps / Quick).

History is stored in localStorage (capped at 50 entries) and can be cleared with Clear.

Division by zero

Division (or modulus) where the denominator is zero triggers:

1. Overheat phase — The UI shifts from cool tones toward a warm glow (respects prefers-reduced-motion).
2. Explosion — The calculator area transitions into a short animated shard burst.
3. Dialog — Explains that division by zero is not allowed; Ok, I get it. resets the flow and clears the expression and on-screen feedback (division-by-zero attempts are not added to history).

Accessibility

Reduced motion skips the overheating/explosion sequence and jumps straight to the division-by-zero dialog.

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License

This project is open source under the MIT License.