Factors, Multiples and Primes Puzzle Set - Worksheets, Questions and Revision

20 original exam-style questions - 4 pages of questions with a full mark scheme - free printable PDF.

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11+ · Number

EP.M108 Factors, Multiples and Primes Puzzle Set

GL ASSESSMENT GL-11PLUS-MATHS · Calculators not allowed · about 55 minutes
Total Marks
Name: _______________________________    Date: ____ / ____ / ______
Answer ALL questions. Show all your working.
1
Which of these numbers is a prime number?
  • A) 39
  • B) 42
  • C) 43
  • D) 45
  • E) 49
(Total for Question 1 is 1 mark)
2
Which of these numbers has exactly three positive factors?
  • A) 48
  • B) 49
  • C) 50
  • D) 51
  • E) 52
(Total for Question 2 is 1 mark)
3
List all the factor pairs of 36.
(Total for Question 3 is 2 marks)
4
Work out the highest common factor (HCF) of 48 and 180.
(Total for Question 4 is 2 marks)
5
Find the lowest common multiple (LCM) of 8 and 12.
(Total for Question 5 is 2 marks)
6
Find the two-digit number between 1 and 100 that is a multiple of 7, is not a multiple of 3, and whose digits add to 7.
(Total for Question 6 is 2 marks)
7
What is the smallest prime factor of 143?
  • A) 7
  • B) 11
  • C) 13
  • D) 17
  • E) 19
(Total for Question 7 is 1 mark)
8
Give an example of a square number less than 100 that has exactly three positive factors.
(Total for Question 8 is 1 mark)
9
Work out the number of positive factors of 72.
(Total for Question 9 is 2 marks)
10
Priya thinks of a number less than 100. It is even, has exactly 6 positive factors, and the sum of its digits is 8. What is Priya's number?
(Total for Question 10 is 2 marks)
11
Which of the following is a prime number?
  • A) 51
  • B) 57
  • C) 59
  • D) 63
  • E) 65
(Total for Question 11 is 1 mark)
12
Write down all the prime numbers between 20 and 40.
(Total for Question 12 is 2 marks)
13
Work out the highest common factor (HCF) of 84, 126 and 210.
(Total for Question 13 is 2 marks)
14
Find the least common multiple (LCM) of 9, 12 and 15.
(Total for Question 14 is 2 marks)
15
A number is the product of two consecutive prime numbers and is less than 100. Find all such numbers.
(Total for Question 15 is 3 marks)
16
Which number could be the difference between two prime numbers both greater than 2?
  • A) 13
  • B) 14
  • C) 15
  • D) 21
  • E) 27
(Total for Question 16 is 1 mark)
17
Find the smallest composite number that has exactly 8 positive divisors.
(Total for Question 17 is 1 mark)
18
A number between 1 and 200 is divisible by both 4 and 9, but it is not divisible by 8. Give the smallest such number.
(Total for Question 18 is 2 marks)
19
Which of the following is NOT a factor of 360?
  • A) 5
  • B) 6
  • C) 9
  • D) 10
  • E) 7
(Total for Question 19 is 1 mark)
20
Find all positive integers n with n < 50 such that n has exactly four prime factors when counted with multiplicity. List them.
(Total for Question 20 is 3 marks)
Mark scheme · EP.M108 Factors, Multiples and Primes Puzzle Set

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15

Question 16

Question 17

Question 18

Question 19

Question 20