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Using prime factorisation to check if two numbers are co-prime
Last updated at August 14, 2026 by Teachoo
Class 6 (Ganita Prakash & Old NCERT)
Chapter 5 Class 6 - Prime Time (Ganita Prakash)
- Factors and Multiples
- Common Multiples
- Common Factors
- Idli Vada Game
- Jumpy Jackpot
- Figure it out - Page 110, 111
- Prime Numbers
- Figure it out - Page 114, 115
- Co-prime numbers (and art)
- Prime Factorisation
-
Uses of Prime Factorisation
- Divisibility Tests
- Figure it out - Page 125, 126
- Fun with numbers
- Teachoo Questions - MCQs
- Teachoo Questions - Mix
- Teachoo Questions - Assertion Reasoning
- Teachoo Questions - Case Based
Transcript
Using prime factorisation to check if two numbers are co-primeCo-prime numbers are those numbers which has only 1 as common factor Thus, if we do prime factorization of both numbers – then we check if numbers do not have any prime common factor What if the common factor is composite? Since only 1 is common factor ∴ 8 & 9 are co-prime We can say that If there are no common prime factors, then the two numbers are co-prime. Checking if 40 and 231 are co-prime Doing prime factorization of each Since 40 & 231 have no common prime factors ∴ They are coprime Checking if 242 and 195 are co-prime Doing prime factorization of each Since 242 & 195 have no common prime factors ∴ They are coprime Checking if 56 and 63 are co-prime Doing prime factorization of each Since 56 & 63 have 7 as common prime factor ∴ They are not coprime
