Concept 5 of 8Foundation
Watch on YouTubeVideoHCF (Highest Common Factor)
HCF = largest number that divides BOTH (or all) given numbers. Also called GCD.
Methods:
- List factors: find common ones, pick biggest.
- Prime factorization: take each common prime at its LOWEST power.
HCF of 12 and 18:
12 = 2² × 3, 18 = 2 × 3². HCF = 2¹ × 3¹ = 6.
Example
HCF of 72 and 120:
72 = 2³×3², 120 = 2³×3×5 → HCF = 2³×3 = 24.
72 = 2³×3², 120 = 2³×3×5 → HCF = 2³×3 = 24.
💡 Tip:HCF solves 'largest equal groups / pieces' problems.
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5 questions to check what you just read.
0 / 5
- Q1.HCF of 12 and 18:
- Q2.HCF of 24 and 36:
- Q3.HCF of 15 and 28:
- Q4.HCF of 45 and 75:
- Q5.HCF of three numbers 12, 18, 24: