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Prime factors HCF and LCM

Free Printable Prime factors HCF and LCM PDF Worksheets, Revision Guide & GCSE Past Paper Questions (Grade 4)

Download free prime factors hcf and lcm worksheets (PDF), GCSE maths past paper questions and worked solutions for Prime factors HCF and LCM (4C). This is a Grade 4 number topic from the GCSE questions by topic collection for Foundation and Higher tier crossover GCSE Maths (Edexcel, AQA, OCR and IGCSE).

The free PDF worksheets table below brings together printable question booklets (Qs) and worked answers or mark schemes (Ans) from IGCSE MT, Maths Genie, Maths4Everyone, Corbett Maths, Maths Made Easy, Naiker Maths, 1st Class Maths, Hannah Kettle, Dr Austin, GCSE Maths Rocket, E Classroom and PMT, along with past paper question booklets.

Below the worksheet links you can read our prime factors hcf and lcm revision notes and worked examples with diagrams, try real GCSE past paper prime factors hcf and lcm questions with step-by-step solutions, or download a PDF of all prime factors hcf and lcm worksheet links.

Free Prime factors HCF and LCM PDF Worksheets & Answers

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GCSE Maths Grade 4 Revision Notes & Method

Guide to Prime factors HCF and LCM: Explanation, Diagrams & Worked Examples

Download Printable One Page Guide (PDF)

Explanation:

To express a number as a product of its prime factors, use a factor tree to split it until every branch ends at a prime number (2, 3, 5, 7, 11, 13…), then write the primes multiplied together in index form (e.g. 2³ × 3 × 5).

To find the HCF and LCM of two numbers, put their prime factors into a Venn diagram: multiply the primes in the intersection (overlap) to get the HCF, and multiply all primes in both circles to get the LCM.

Example 1: Write 140 as a product of its prime factors in index form.

140 2 70 2 35 5 7
140 = 2 × 70
70 = 2 × 35
35 = 5 × 7
2² × 5 × 7

Example 2: Given 60 = 2² × 3 × 5 and 84 = 2² × 3 × 7, find the HCF and LCM.

60 84 5 2, 2 3 7 Overlap = HCF = 12
HCF = 2×2×3 = 12
LCM = 12×5×7
= 420
Scanned GCSE Exam Questions & Worked Solutions

GCSE Past Paper Prime factors HCF and LCM Questions & Answers

Past Paper Example 1 GCSE Jun 2025 2F Q20 / 2H Q1 4 marks
Work out
(a) Express 250 as a product of its prime factors. (2)
(b) Find the lowest common multiple (LCM) of 30 and 25 (2)
(a) Express 250 as a product of its prime factors. [2 marks]
(b) Find the lowest common multiple (LCM) of 30 and 25 [2 marks]
Worked Solution & Mark Scheme (4 marks)
Part (a) Solution:
250 = 2 × 125 = 2 × 5³ M1 A1
Answer (a): 2 × 53
Part (b) Solution:
30 = 2 × 3 × 5 M1
25 = 5²
LCM = 2 × 3 × 5² = 150 A1
Answer (b): 150
Past Paper Example 2 GCSE Nov 2023 1F Q20 / 1H Q3 4 marks
Work out
(a) Write 156 as a product of its prime factors. (2) (b) Find the highest common factor (HCF) of 156 and 130 (2)
(a) Write 156 as a product of its prime factors. [2 marks]
(b) Find the highest common factor (HCF) of 156 and 130 [2 marks]
Worked Solution & Mark Scheme (4 marks)
Part (a) Solution:
156 = 2 × 78 = 2 × 2 × 39 = 2² × 3 × 13 M1 A1
Answer (a): 22 × 3 × 13
Part (b) Solution:
130 = 2 × 5 × 13 M1
HCF = 2 × 13 = 26 A1
Answer (b): 26
Past Paper Example 3 Eduqas Nov 2018 2F Q23 7 marks
Gregor owns a restaurant.
(a) The diagram shows a circular place mat. [2 marks]
14 cmDiagram not drawn to scale
The radius of the circular place mat is 14 cm.
Calculate the circumference of the circular place mat.
(b) Gregor plans to buy some spoons and forks.
A bag of 24 spoons costs £19.95.
A box of 18 forks costs £15.55.
Bags and boxes cannot be split.
Gregor decides to buy the same number of spoons as forks.
He places an order to buy the smallest number of each that he can.
Complete the details on the order form shown below.
You must show all your working.
@@TABULAR0@@
[5 marks]
Worked Solution & Mark Scheme (7 marks)
Part (a) Solution:
C = 2 * π * r = 2 * π * 14 = 28π ≈ 87.96 cm (or 2 * 3.14 * 14 = 87.92 cm). M1 A1
Answer (a): 87.96 cm (or 88 cm, 87.92 cm)
Part (b) Solution:
Smallest common multiple of 24 and 18 is 72 M1
Bags of spoons = 72 / 24 = 3 bags M1
Cost of spoons = 3 * 19.95 = £59.85 M1
Boxes of forks = 72 / 18 = 4 boxes M1
Cost of forks = 4 * 15.55 = £62.20
Total cost = 59.85 + 62.20 = £122.05. A1
Answer (b): 3 bags of spoons (£59.85), 4 boxes of forks (£62.20), Total = £122.05

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