Comprehensive Calculator Guide
This calculator checks whether two numbers are relatively prime, sharing no divisor but 1, via their greatest common divisor, and gives their least common multiple. 15 and 28 are coprime though both are composite; 12 and 18 share 6.
Coprime numbers
Two numbers are coprime when their GCD is 1. Consecutive numbers are always coprime. For coprime numbers the LCM is their product; otherwise LCM = product ÷ GCD.
How to Use
- Enter the first number.
- Enter the second.
- Press “Check” to see the GCD, whether they are coprime and the LCM.
Formula Used
Coprime when GCD = 1; then LCM = a × b
Practical Examples
- Example 1
- 15 and 28: coprime, LCM 420.
- Example 2
- 12 and 18: GCD 6, LCM 36.
Important Tips
- Two even numbers are never coprime.
- Compare prime factors.
- Use Euclid’s algorithm for big numbers.
Common Mistakes to Avoid
- Thinking both must be prime.
- Confusing prime and coprime.
- Multiplying for the LCM without checking.
Frequently Asked Questions
- 8 and 9?
- Coprime.
- 14 and 21?
- No, both divide by 7.
- Is 1 coprime with everything?
- Yes.