Prime Factors, HCF & LCM (Edexcel IGCSE Maths): Exam Questions

Write 300 as a product of its prime factors. Show your working clearly.

$A=2\times2\times2\times3\times3\times5$

$B=2\times2\times3\times3\times3\times5$

Find the lowest common multiple (LCM) of $5A$ and $7B$ Show your working clearly.

Find the Highest Common Factor (HCF) of 140 and 245.

A machine has a buzzer that sounds every 50 minutes. The machine also has a bell that sounds every 80 minutes.

The buzzer and the bell sound together at 10 am.

Find the time at which they next sound together.

Write 300 as a product of its prime factors. Show your working clearly.

$A=2\times2\times2\times3\times3\times5$

$B=2\times2\times3\times3\times3\times5$

Find the lowest common multiple (LCM) of $5A$ and $7B$ Show your working clearly.

$A=5^{3}\times7^{3}\times11^{6}$ and $B=5^{6}\times7^{2}\times11^{4}$

Find the highest common factor (HCF) of $A$and $B$ Give your answer as a product of powers of its prime factors.