Exploring Integers in SageMath: A Hands-On Introduction

- April 21, 2025

SageMath makes working with integers super intuitive — from checking primality to exploring number theory!

Today, we dive into SageMath tools that make integer exploration easy, visual, and real-world-ready!

1. Basic Integer Operations

Checks if n is an integer.

Is n prime?

Factorize n:

Find next and previous primes:

Find divisors of n:

2. Digging into Digits

Bigger Number Example:

3. Division and Remainders ➗

Example:

📈 Visual Reinforcement: Division Formula

Variable	Value
a	7642
b	63
q	121
r	19

Check in SageMath:

4. GCD and Extended GCD 🔄

Finding GCD:

Extended GCD (Bezout's Identity):

📈 GCD Process Flowchart:

5. Real-World Cryptography with SageMath 🔐

Encrypt a Simple Message:

Decrypt the Message:

📈 How Key and Modulus are Derived:

Choose two primes
Calculate modulus:
Calculate
Choose encryption key such that
Compute decryption key

6. Prime Numbers and Euler’s Phi Function 🔢

Counting Primes:

Euler’s Phi Function:

7. Huge Numbers: Factorials 📈

Calculating and Exploring Factorials:

Analyzing Digits:

8. Real Numbers and Approximations

9. Working with Arrays (NumPy + SageMath)

✍️ Practice Exercises

Exercise	Hint
Find LCM and verify relation with GCD	Use
Extended GCD for three integers	Apply
Factors of sum of digits of	Use
Count integers coprime to 12 between 62 and 672	Use a simple for loop with
Find n such that	Try
Compute Euler’s phi function manually	Loop and count with

⚡ Efficiency Highlights

SageMath handles huge numbers (factorials, big primes) effortlessly.
Backed by GMP, MPFR, FLINT libraries for high-speed computation.
Practical for cryptography, combinatorics, and real-world number theory.

🌍 Join the Learning Community

🎯 Your Challenge:

Solve exercises, create your own SageMath projects, or explore a new number theory concept!

📬 Share your work:

Post your GitHub repository links or paste SageMath code snippets in the comments!

🔮 What’s Next?

Get ready for upcoming posts:

Symbolic Computation: Solving algebraic equations and calculus in SageMath
Graph Theory: Building graphs and analyzing networks
Cryptography Toolkit: Generate your own RSA keys
Advanced Number Theory: Dive into Pell’s Equation and Elliptic Curves

🎉 Conclusion

SageMath transforms working with integers into an exciting adventure — from basic division to powerful cryptographic applications!
Through visualization, exploration, and real-world connections, you can master computational mathematics one step at a time.

Keep Exploring, Keep Creating! 🚀

🔔 Next Challenge Topic Preview

"Solving Equations in SageMath"

SageMath isn't just about numbers—it's a powerhouse for solving equations! In this challenge, you'll explore everything from basic algebraic equations to advanced systems of equations. Highlights include:

Single-Variable Equations
Like: Solve (x^2 - 5x + 6 = 0).
Systems of Linear Equations
Solve real-world problems with equations like (2x + 3y = 5) and (x - y = 1).
Non-linear Equations and Applications
Dive into quadratic, exponential, and trigonometric equations.

Heuristic Computation and the Discovery of Mersenne Primes