# Nap1 — Your first number theory app! > Number theory education app with arbitrary precision calculator and cryptography examples. (iPhone/iPad app by Ferra Solutions (Pty) Ltd.) - Source: https://appshunter.io/ios/app/nap1/id964514021 (this page in markdown: same URL + `.md`) - Developer: [Ferra Solutions (Pty) Ltd](https://appshunter.io/developer/964514020) - Category: Education, Utilities - Price: Free with in-app purchases - Rating: 5.00/5 from 1 App Store ratings · 4 written reviews indexed - Age rating: 4+ - Requires: iOS 8.0 · 6 MB - Languages: English - Released: 2015-02-25 - Data updated: 2026-06-10 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/nap1/id964514021/reviews.md ## What is Nap1? Number theory giving you sleepless nights? Take a nap - Nap1. Nap1 is your first number theory application. Calculate accurately up to 100,000 digits (40,000 on older devices) using its free arbitrary precision calculator. Then use one of the many special purpose calculators that implements algorithms such as the Euclidean algorithm, linear congruence theorem or Chinese remainder theorem. All these provide detailed, step by step explanations of the algorithm. Then see how these are applied today in the encryption section and learn how to encrypt and decrypt secret messages. Learn number theory concepts such as - modulus and congruence - prime numbers (including a powerful primality tester and large prime number finder) - Euclidean algorithm to calculate the GCD with - extended Euclidean algorithm to solve for the GCD coefficients - linear congruence theorem and modular multiplicative inverses - congruent powers by successive squaring - congruent roots - Chinese remainder theorem to solve simultaneous congruences or share secrets with - Fermat's little theorem, Euler's phi and Garner's formula - Egyptian fractions and the Erdős-Straus conjecture. After mastering these, move on to encrypt and decrypt secret messages. Learn how these concepts are applied today in the RSA Cryptosystem and see all the calculations required in detail. History Nap1 was born in a South African mathematics club. The following gives a brief overview of how that happened. It was written by Dr Danie Brink. I am a South African number theory enthusiast who teaches some of the principles of number theory to high school students in South Africa. I do this at a math club in the afternoon in Pretoria, South Africa. The math club is an extramural activity for students who are talented at mathematics and who like to do math just for the fun of it. At math club, we look at modular arithmetic and congruence, Fermat’s Little Theorem, Euler’s Formula, the Euler Phi-function, the Euclidean algorithm and consecutive squaring. The highlight of the course is where we combine these skills and use them to encrypt messages using the RSA algorithm. The culmination of the course happens when I publish a secret message on the Internet at a specific time. Students have to access the Internet at this time, from the comforts of their own homes, and use their number theory skills and knowledge of the RSA method to decrypt the message. When they have successfully decrypted the secret message, they text this message to my phone. Students also have to take pictures of all their work and send that to me – we do this so that we can verify that no other tools, other than paper, pencil and a basic calculator has been used to do the math. I sit at home and verify the message and declare a winner. I am currently busy with the fifth course and students are loving it every time. Last year, I invited adults to take part and this is where I met MG Ferreira, a very clever mathematician. MG quickly caught on to the course and was soon writing programs to do the encryption and decryption at the click of a button. We had breakfast together and decided to write a number theory app. That day was the start of the very difficult birth of the world’s best (and by all accounts, first) number theory app, called NAP1. ## Key features - Arbitrary precision calculator - Special purpose calculators - Step-by-step algorithm explanations - Number theory concept learning - Primality tester and prime finder - Encryption and decryption examples - RSA Cryptosystem application ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Theory Power I | $2.99 | one-time | | Crypt Power I | $2.99 | one-time | | Combo Power I | $4.99 | one-time | ## Recent user reviews (4 of 4) All indexed reviews: https://appshunter.io/ios/app/nap1/id964514021/reviews.md ### 5/5 — What is the asterisk for? *2018-02-15, version 1.7.0* There is an asterisk on the calculator screen, just below the info symbol. It changes to a circle when you select it. I have not found an explanation for it anywhere on the theory pages or the YouTube videos. **Developer response:** The ‘splat’ will turn the key click sound on or off. ### 5/5 — Great Addition!!! *2016-08-05, version 1.6.0* Has everything I have been searching for!!! Half of the theories and mathematical encryptions are in-app purchases. But can be easily restored on your devices after purchase. Customer Support is quick and friendly. It has everything you will look for; from modular arithmetic to RSA encryption. ### 5/5 — excellent *2015-04-19, version 1.3.0* I love this app so useful I highly recommend it ### 5/5 — Brilliant *2015-04-18, version 1.3.0* This is a great app for all you math lovers. And for you non math lovers there are functions that are amazing. You can even make codes that are impossible to crack! Great app ## Frequently asked questions about Nap1 ### What number theory concepts does Nap1 teach? Nap1 covers modulus and congruence, prime numbers (including a primality tester), Euclidean algorithm, linear congruence theorem, Chinese remainder theorem, Fermat's little theorem, Euler's phi, Egyptian fractions, and the Erdős-Straus conjecture. ### How accurate is the calculator in Nap1? The app features an arbitrary precision calculator that can accurately calculate up to 100,000 digits, or 40,000 digits on older devices. ### Does Nap1 explain how number theory is used in real life? Yes, Nap1 demonstrates practical applications of number theory concepts in encryption and decryption, specifically detailing calculations for the RSA Cryptosystem. ### What are the special purpose calculators in Nap1? Nap1 includes special purpose calculators that implement algorithms like the Euclidean algorithm, linear congruence theorem, and Chinese remainder theorem, all with detailed step-by-step explanations. ### Is Nap1 suitable for beginners in number theory? Yes, Nap1 is designed as a first number theory application, providing foundational concepts and clear explanations suitable for those new to the subject. ### What devices does Nap1 support? Nap1 is available for iPhone, iPad, and iPod devices. ### How often is Nap1 updated? The latest version of Nap1 is 1.8.1, which was last updated on March 7, 2019. ### What is the age rating for Nap1? Nap1 has an age rating of 4+, making it suitable for a wide range of users. ## Version history (last 1 release) ### 1.8.1 — 2019-03-07 Bug fixes and improvements. ## Apps similar to Nap1 | App | Rating | Price | Category | | --- | --- | --- | --- | | [New York City Subway 3D Map](https://appshunter.io/ios/app/new-york-city-subway-3d-map/id1242496960) | 3.5 (4) | Free | Education | | [KaleidoTile](https://appshunter.io/ios/app/kaleidotile/id1374849164) | 4.1 (7) | Free | Education | | [Algorithms (VPP compatible)](https://appshunter.io/ios/app/algorithms-vpp-compatible/id1128330932) | 5.0 (2) | $2.99 | Education | | [Athens Christian School](https://appshunter.io/ios/app/athens-christian-school/id6443741781) | 4.0 (8) | Free | Education | | [Sundial 3D Science Experiment](https://appshunter.io/ios/app/sundial-3d-science-experiment/id1560688425) | 5.0 (2) | Free | Education | | [4D Draw](https://appshunter.io/ios/app/4d-draw/id926050711) | 3.3 (7) | Free | Education | ## More apps by Ferra Solutions (Pty) Ltd - [fdm ferra data models](https://appshunter.io/ios/app/fdm-ferra-data-models/id1214202805) - [ferra value my business](https://appshunter.io/ios/app/ferra-value-my-business/id1538135904) - [Pyramid Connect](https://appshunter.io/ios/app/pyramid-connect/id1543944901) - [Tupper](https://appshunter.io/ios/app/tupper/id1557490476) All apps by Ferra Solutions (Pty) Ltd: https://appshunter.io/developer/964514020 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*