Finding HCF using Prime Factorisation
Last updated at January 22, 2026 by Teachoo
Finding HCF using Prime Factorisation
Finding HCF using Prime Factorisation
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Class 7 (Ganita Prakash 1, 2 & old NCERT)
Chapter 3 Class 7 - Finding Common Ground (Ganita Prakash II)
- The Greatest of All
- Prime Factorisation
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Finding HCF using Prime Factorisation
- Figure it out - Page 54
- Least, but not Last!
- Finding LCM using Prime Factorisation
- Patterns, Properties, and a Pretty Procedure!
- Figure it out - Page 59
- Miscellenaous Questions on HCF, LCM
- Efficient Procedures for HCF and LCM
- Property Involving both the HCF and the LCM
- Figure it out - Page 63, 64
Transcript
Finding HCF using Prime FactorisationHCF means HIghest Common Factor. It means the greatest number which can divide the given numbers HCF is also known as Greatest Common Divisor (GCD) Find HCF of 4 & 6 To find HCF , we do prime factorization of 4 & 6 separately 4 = 2 × 2 6 = 2 × 3 HCF of 4 & 6 = 2 Find HCF of 12 & 16 To find HCF , we do prime factorization of 12 & 16 separately 12 = 2 × 2 × 3 16 = 2 × 2 × 2 × 2 HCF of 12 & 16 = 2 × 2 = 4 Find HCF of 20, 28, 36 Doing Prime factorization of 20, 28 & 36 separately 20 = 2 × 2 × 5 28 = 2 × 2 × 7 36 = 2 × 2 × 3 × 3 So, HCF of 20, 28 & 36 = 2 × 2 = 4 HCF of 13 & 23 Now, 13 = 13 23 = 23 Since there are no common prime factors , only 1 will be the common factor ∴ HCF = 1
