App Overview

GraphNCalc83 icon

GraphNCalc83

Ernest Brock · Education

GraphNCalc83 uses touch, color and blazing speed to handle your math problems

$12.99 · In-app purchases

PRICE
$12.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.9
4,037 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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Build Kit

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A product spec, screen plans, and build steps for your coding agent.

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What's included19 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 GraphNCalc83: 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

Offer more diverse graph types and customization options.

Assumption to check: Limited graphing options compared to advanced calculators

Validate with people who use this workflow before building.

Hypothesis 2

Provide a more affordable subscription model.

Assumption to check: High price point for features

Validate with people who use this workflow before building.

Hypothesis 3

Simplify the interface and provide better onboarding tutorials.

Assumption to check: User interface can feel overwhelming for beginners

Validate with people who use this workflow before building.

Hypothesis 4

Enable offline access for previously calculated graphs and functions.

Assumption to check: No offline functionality

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

GraphNCalc83 uses touch, color and blazing speed to handle your math problems. The familiar calculator keyboard, arrow keys and functions are enhanced with full touch input for all graphs, editors and menus. Enter calculations in natural textbook format. Enter fractions and view result as fractions. Trace graphs with your finger. Zoom in and out with a pinch. Explore regressions with a tap on the screen. Scroll through the list, matrix and calculation history with a swipe. Tap the ? key for help. Written using the latest 64 bit math libraries, GraphNCalc83 harnesses the amazing computing resources of the iPhone and iPad to provide a colorful, fast and fluid experience. Graphs scroll, glide and zoom smoothly. Matrix, statistics and BASIC programs run 500x times faster than traditional calculators. GraphNCalc83 includes: Algebraic entry: Enter problems using full algebraic textbook notation. The command line editor includes interactive parenthesis matching and high lighting, undo and redo, bubble function help and a 200 level calculation history and recall stack. Generate a PDF report of calculations for mailing or printing using the SEND function. Math functions: Trigonometry, logarithms, function minimum, maximum, numeric integration and derivatives, general solver, real and imaginary numbers, combination, permutation, random number generation, normal, T, chi squared, Fisher, poisson and geometric distributions, binary shift and rotate, test and logic operations, list operations including sort, std. deviation, sum, sequence, matrix determinant, transpose, sum, ref, rref, addition, multiplication. Graph functions, parametric, f(x,y) and polar equations and statistics plots: Full color graphs with touch to trace, pinch zoom, function minimum, maximum, intersections, asymptotes and numeric integration. Output graphs in high resolution PDF format for mailing or printing. Interactively explore function behavior using variables tied to slider bars. Statistics, Inferential Statistics and Distributions: A set of inferential statistics worksheets and graphs of distributions are included. The regression analysis screen allows you to quickly compute, view and analyze a data set using a variety of curve fitting methods. Table: Analyze functions using the table viewer. Use the split screen mode to simultaneously view a graph and table. Matrix and Lists: Matrix and list editors and a full set of matrix and list operations are built in. Unit Converter and Constants: Convert between a wide variety of scientific, engineering and common units. A large set of physical constants are also included. BASIC programming: Create, edit, debug and run BASIC programs. Programs run more than 500 times faster than traditional calculators. Import and execute .83p and .8xp files. Chemistry: The calculator includes a full featured periodic table, a mass calculator and a data base of element properties. The touch interface allows you to view and interact with the periodic table to view by series, state, melting point, boiling point, electronegativity, electron affinity, valence, ionization, radius, hardness, modulus, density, conductivity, heat and year discovered. Geometry: The geometry application computes perimeter and area for a variety of 2d geometric figures including squares, rectangles, parallelograms, triangles, polygons, circles, arcs and ellipses. A full triangle solver and interactive unit circle grapher are built in. Solve line intersections, project a point to a line and find a circle given 3 points. Finance: Compute time value of money problems including annuities, lump sums and uneven cash flow analysis with IRR and NPV Built-in user guide: A user guide is included and is a touch away using the ? key or ⓘ on any menu. All functions have a full manual page with description of arguments and examples of use. Pop up bubble help displays function arguments during problem entry and program editing.

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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.

SUGGESTED BUILD STACK
React Native
Expo
Zustand
React Navigation
react-native-reanimated
expo-graphics
BUILD KIT DIFFICULTY
Advanced

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.