App Overview

MathU 12D Financial Calculator icon

MathU 12D Financial Calculator

Creative Creek, LLC · Finance

"5 stars - This app is great

$4.99 · In-app purchases

PRICE
$4.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.8
96 ratings · Top 5%

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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What's included15 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.

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.

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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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for MathU 12D Financial Calculator: map the core Finance 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 calculation types to include more financial scenarios.

Assumption to check: Limited calculation options compared to competitors

Validate with people who use this workflow before building.

Hypothesis 2

Implement a guided onboarding process to ease new users.

Assumption to check: Difficult to navigate for new users

Validate with people who use this workflow before building.

Hypothesis 3

Add animations or visual aids to enhance user engagement during calculations.

Assumption to check: Lack of visual feedback on calculations

Validate with people who use this workflow before building.

Hypothesis 4

Introduce cloud syncing for user history and settings.

Assumption to check: No cloud backup for history

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

"5 stars - This app is great. Very Quick. Would highly recommend". See more in customer reviews. MathU 12D, the Deluxe Financial RPN Calculator, is written from the ground up to behave exactly like and surpass the classic HP-12C. MathU 12D uses the same RPN (Reverse Polish Notation) entry system and supports the same mathematical functions as the HP-12C. In fact, if you are familiar with the HP-12C you will be able to use MathU 12D right away. Supports iPhone, iPad and macOS. First released in 2010, the calculator continues to be updated with new features as iOS improves. Made by Creative Creek, LLC. We have been making calculators for mobile devices for over 25 years. Also check out MathU RPN, our advanced scientific and financial RPN calculator. MathU 12D adds some big improvements over the original HP-12C: 1) Visible Financial Registers -- The values of the financial registers are displayed prominently above the associated buttons. This allows you to quickly verify that the loan parameters are correct and builds confidence in the results. 2) Computation Speed -- You will be amazed how quickly MathU 12D produces results. Even complicated calculations like the determination of interest rate, IRR or NPV are finished in a fraction of a second. 3) Two line display -- A two line display can be chosen so that the x and y register values are always visible. You can immediately see results and verify input values. 4) Visible Programming -- Program lines are displayed using the function name instead of the key pad location. This makes reading and writing MathU 12D programs easier. 5) 20 Registers unaffected by programs - The registers are not shared with the program space so you can create up to 99 line programs without sacrificing any storage space. Documentation for MathU 12D is available from within the app. All the functions work exactly the same as on the HP-12C, so if you are familiar with the HP-12C you will be able to use MathU 12D right away. Features - Fast and accurate computation based on IEEE double precision (up to 16 digits) - 5 financial registers (visible on the main screen) - 20 storage registers - Programmable with up to 99 program steps - Program steps show function name directly - Two line display - FIX, SCI, and ENG display modes - Access to on-line documentation - Settings screen - Thousands and decimal separators follow international format settings - Copy and paste support - Support for iOS 8.x or higher. - Support for iPhone and iPad Functions Supported: - Time value of money (N,i,PV,PMT,FV) - Net Present Value (NPV) - Internal Rate of Return (IRR) - Simple interest - Cash Flows (CF0, CFj, Nj) - Bond pricing and yield (PRICE, YTM) - Depreciation based on - Straight line (SL) - Sum-Of-the-Years-Digits (SOYD) - Declining balance (DB) - Date in future (DATE) or days between dates (DYS) - Statistics mean, std, wieghted mean, factorial - Percent, percent change and percent of total - Linear curve fitting (x,r y,r) - Scientific functions (y^x, e^x, sqrt, 1/x, ln) - Integer and fractional parts (INTG, FRAC) Requires iOS 16.6+

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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.

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BUILD KIT DIFFICULTY
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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.