Feature spec
Goal: Send a clear invoice after finishing a job.
- Add a client, line items, a due date, and payment instructions.
- Preview the total before exporting a PDF.
- Keep an editable draft if export fails.
App Overview
Fast Facts Math
There are eight reasons why this is the best Math Facts App on the market:
$0.99
PRICE
$0.99
No in-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 3.6
14 ratings · Top 50%
Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.
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Build Kit
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A product spec, screen plans, and build steps for your coding agent.
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What's included14 files
A product spec, phased build plan, differentiation notes, and screen references.
- START_HERE
- AGENTS
- EVIDENCE
- SPEC
- BUILD_PLAN
- DIFFERENTIATION
- skills/
- screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.
Screen plan
Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.
States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.
Differentiate and validate
Hypothesis: Contractors need faster repeat invoices more than more templates.
First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.
The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.
Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.
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Free quick prompt For a smaller starting point
Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for Fast Facts Math: map the core Education workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
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Opportunities
AI-GENERATED OPPORTUNITY HYPOTHESES
These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.
Hypothesis 1
Expand options to include advanced topics like fractions and decimals.
Assumption to check: Limited math operations compared to other apps
Validate with people who use this workflow before building.
Hypothesis 2
Implement adaptive quizzes based on user performance.
Assumption to check: No personalized learning paths
Validate with people who use this workflow before building.
Hypothesis 3
Add gamified elements like rewards and streaks to engage users.
Assumption to check: Lack of interactive elements
Validate with people who use this workflow before building.
Hypothesis 4
Collect user feedback to identify and address pain points.
Assumption to check: 3.6/5 rating indicates user dissatisfaction
Validate with people who use this workflow before building.
App evidence
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
App Store description
There are eight reasons why this is the best Math Facts App on the market: 1) Use one of our lists or choose individual facts 2) Choose Multiple choice or exact answer 3) Set a time limit to answer; prevent counting 4) RACE the clock feature: enter your name in the Top Ten 5) Option for a mini-lesson if you get one wrong 6) Facts are displayed in four different ways 7) Smart Review: You get extra practice with the facts you miss. There is even an option to review the facts you missed from the previous study session 8) Detailed progress report after each session that can be e-mailed and printed This is simply the best math facts app on the market. It was created by a Third Grade Teacher with a post graduate degree in Curriculum and Instruction. There are free apps out there, but they don’t have all the features that make FastFacts so effective at helping young people master math facts. For less than the cost of flashcards you can give your children/students the best math facts app.
Written user reviews are not shown here. Check current App Store reviews >
Screenshots
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Build scope
Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.
Define the first version
Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.
Set boundaries
Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.
Check the hard parts
Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.
SUGGESTED BUILD STACK
React Native
Expo
React Navigation
Victory Native
Formik
@expo/vector-icons
BUILD KIT DIFFICULTY
Starter
From the Build Kit assessment.
A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.
