Practice and Revision - HCF and LCM
Let us practise and revise what we learned about hcf and lcm. HCF (Highest Common Factor) is the largest number dividing two numbers exactly
Core concept
To find HCF, we list the factors of each number and identify the largest factor common to both.
How it works
For example, factors of 12 (1,2,3,4,6,12) and 18 (1,2,3,6,9,18) share 6 as their highest common factor.
Why it matters
To find LCM, we list multiples of each number and find the smallest multiple common to both.
Key detail
HCF and LCM are useful in simplifying fractions, solving problems about grouping items, and finding common time intervals.
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Quick notes
• HCF is the largest common factor of numbers.
• LCM is the smallest common multiple of numbers.
• Factors of 12: 1,2,3,4,6,12.
• Factors of 18: 1,2,3,6,9,18.
• HCF of 12 and 18 is 6.
• LCM uses common multiples of numbers.
• HCF and LCM help simplify fractions.
• They help solve grouping and interval problems.