Numbers (P6) Practice
Master prime and composite numbers, HCF, LCM, prime factorisation, and number patterns including perfect squares and cubes. These concepts underpin fractions, algebra, and data interpretation.
Common Mistakes to Avoid
Confusing HCF (largest divides both) with LCM (smallest both divide into)
Forgetting that 1 is neither prime nor composite
Errors in prime factorisation β missing a factor or stopping too early
Practice Questions
Try each question. When you're stuck, reveal the Socratic strategy β a guided hint that teaches you how to think, not just what to write.
Find the HCF of 24 and 36.
What is the LCM of 8 and 12?
Express 180 as a product of its prime factors.
Parent & Tutor Insight
HCF and LCM appear not just in standalone questions but also embedded in fraction and algebra problems. Students who can find HCF/LCM quickly have a significant speed advantage across the paper.
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Common Questions
What is the difference between HCF and LCM?
HCF (Highest Common Factor) is the largest number that divides exactly into both numbers. LCM (Lowest Common Multiple) is the smallest number that both numbers can divide into exactly. Memory aid: HCF β divide; LCM β multiple.
Are perfect squares and cubes tested in PSLE?
Yes. Students should know the squares of 1β20 and cubes of 1β5. Questions may ask: 'Is 144 a perfect square?' or 'What is the smallest number to multiply 72 by to get a perfect square?'
What is a prime number?
A prime number has exactly two factors: 1 and itself. The first 10 primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29. Note: 1 is NOT prime (it has only one factor). 2 is the only even prime.