calcMod vs Rectangles & Primes
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
calcMod
This application helps users perform complex mathematical calculations, including factorials, primality tests, and modular arithmetic. It's designed for students and educators interested in number theory and the properties of integers.
- Factorial calculation up to 80!
- Primality testing with change mod function
- Divisor identification
- Modular exponentiation
- Modular inverse calculation
- Number storage and recall
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What are all the digits of the factorial of 79 and how many digits ? Want to know if a big integer is prime ? The change mod function indicates when the number is prime. Want to know the divisors of an integer ? A prime divisor has no inverse modulo this integer. The "n!" button calculates the factorial of an integer from 0 to 80. Factorial are limited to factorial of 80, but the calculator could calculate them up to 2000 ! (ProX version) The "change mod" (change modulo) function indicates when the modulo is prime. There is a limit to 10^10 for modulo in this FREE version (no limit with ProX version). You can stoke one number and recall it when you want. The "Mod" operation indicates the residue modulo N. The exp function allow modular exponentiation (as + - *) The "INV" function calculates the inverse of an integer modulo N. This app is intended for both mathematics teachers and/or their students, or if you are interested in the beauty of numbers. Enjoy calcMod-Light ! Les commentaires sont disponibles en français (réglages).
Rectangles & Primes
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Rectangle provides a fun and insightful maths experience for kids aged 6 to 12. They will improve their understanding of number factorization and prime numbers.
Screenshots
Verdict
The clearest difference is update cadence: Rectangles & Primes at every 3 weeks against calcMod's every 18 months. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
calcMod ships an update every 18 months, Rectangles & Primes every 3 weeks. Both last shipped on October 2, 2026.
| Parameter | calcMod | Rectangles & Primes |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 18 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 1 MB | 10 MB |
| Age rating | 4+ | 4+ |
| Developer | Alain Cardinaux | Johannes Charra |
In-app purchases
calcMod
No in-app purchases
Rectangles & Primes
No in-app purchases
Questions
Is calcMod free?
Is Rectangles & Primes free?
Do calcMod or Rectangles & Primes have ads?
Which is updated more often, calcMod or Rectangles & Primes?
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