Deck Odds

Deck Odds is an offline probability study notebook that uses a standard 52-card deck as a transparent teaching model. Mark which cards have already been drawn, then read exact remaining-deck counts, combinatorial expansions, and conditional-probability steps—with worked plain-language explanations you can verify by hand. Built for students, tutors, and self-learners. It is a reference and classroom tool only: no money, stakes, wagering, betting odds, or games of chance. DRAWN-STATE CARD GRID Tap any of the 52 face cards (4 suits × 13 ranks) to toggle Drawn vs Still-in-deck. Live counters show remaining total, per-suit, per-rank, and per-color counts as the sample space shrinks. EVENT BUILDER WORKSPACE Choose a target event from teaching presets—next card is a heart, exactly two spades in the next three draws without replacement, full-house shape in a 5-card remainder sample—or define your own rank and suit constraints. The panel recomputes P(event | drawn so far) instantly. STEP-BY-STEP COMBINATORICS Expand every result as ordered conditional factors and as combination ratios C(remaining favorable, k) / C(remaining, k). Each intermediate integer is shown so learners can check the arithmetic themselves. WORKED EXPLANATION PANE Paired plain-English narrative and formal notation cover the current setup: independence versus without replacement, and why the denominator changes after each drawn card. Always framed as math study—not play advice. SCENARIO LIBRARY Open pre-seeded classroom notebooks such as “seven cards already out, probability next is an ace,” flush-draw remainder counts, and conditional pair after visible ranks. Each loads a full drawn grid plus a target event. QUIZ MODE Multiple-choice and numeric-entry items generated from the same remaining-deck model: identify remaining favorable counts, pick the correct conditional probability, or complete a missing C(n,k) term. Immediate reveal shows the correct expansion and a short remediation note. PERSONAL NOTEBOOK HISTORY Save named analyses—drawn-set snapshot, event definition, final probability, and step list—into an on-device list. Reopen any entry to keep editing the grid or re-export. PDF AND SHARE EXPORT Render the current grid summary, event statement, numeric result, and full step-by-step derivation into a clean multi-section PDF via the system share sheet for printing, homework submission, or tutor review. Deck Odds turns abstract conditional probability and combinatorics into a concrete, inspectable deck state—so every path from “cards left” to a final probability is visible, checkable, and ready for study notes.