# Javascript UI Math

> Use JavaScript number math safely for front-end UI behavior, including expressions, precedence, coercion, NaN, Infinity, floating-point precision, BigInt limits, modulo wrapping, rounding, random values, and repeatable UI randomness. Use when building sliders, carousels, counters, animation values, randomized UI, financial-ish display values, or debugging numeric edge cases in browser JavaScript.

- Skill: `lvtd-llc/javascript-ui-math` (Agent Skill, multi-file: 10 files)
- Install (CLI): `npx skillmds@latest add lvtd-llc/javascript-ui-math`
- Raw SKILL.md: https://api.skillmd.com/api/skills/lvtd-llc/javascript-ui-math/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: MIT
- Author: LVTD-LLC (https://skillmd.com/u/lvtd-llc)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/lvtd-llc/javascript-ui-math

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# JavaScript UI Math

Use this skill for numeric browser behavior that needs predictable edge-case handling. It helps avoid common JavaScript traps around coercion, precision, modulo behavior, rounding, randomization, and BigInt.

## Quick Start

1. Read `guidelines.md` to select the smallest relevant file set.
2. Load `references/ui-numbers/rules.md` for implementation decisions.
3. Load `references/ui-numbers/examples.md` when editing code.
4. Use `workflows/debug-ui-number-logic.md` for multi-step derivation or debugging.

## Contents

| Resource | Purpose |
|----------|---------|
| `guidelines.md` | Routes tasks to the right reference files |
| `references/source-map.md` | Book source and chapter/section traceability |
| `references/ui-numbers/knowledge.md` | Core concepts and terminology |
| `references/ui-numbers/rules.md` | Practical rules, guidelines, and exceptions |
| `references/ui-numbers/examples.md` | Bad/good examples and refactoring approach |
| `references/ui-numbers/patterns.md` | Reusable formula and implementation patterns |
| `references/ui-numbers/checklist.md` | Review checklist and red flags |
| `workflows/debug-ui-number-logic.md` | Step-by-step workflow |

## Source

Derived from *Math for Web Design* by Paul McFedries, Chapter 2: Math basics for JavaScript.
Citations are tracked in `references/source-map.md`.