Printable · GCSE Foundation · ages 14-16

Factors, multiples, primes, HCF and LCM worksheet — GCSE Foundation

Fifteen questions on "factors, multiples, primes, hcf and lcm" — DfE statement N4. Print it, or print three versions so neighbours cannot copy by letter; the key gives the letter for each version.

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Factors, multiples, primes, HCF and LCM worksheet — GCSE Foundation

Maths · GCSE Foundation · N4 · Factors, multiples, primes, HCF and LCM · 15 questions

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1.Work out the highest common factor of 12 and 18.
(a)2
(b)6
(c)36
(d)3
2.A number, n, is a multiple of both 6 and 9. Work out the smallest possible value of n that is greater than 20.
(a)36
(b)18
(c)54
(d)27
3.Work out the lowest common multiple of 4 and 6.
(a)12
(b)2
(c)6
(d)24
4.Work out the lowest common multiple of 9 and 15.
(a)24
(b)45
(c)135
(d)3
5.Two lighthouses flash at the start of the same minute. The first lighthouse flashes every 8 minutes and the second flashes every 12 minutes. Work out how many minutes it will be until they next flash together.
(a)4
(b)24
(c)96
(d)20
6.At a bus station one bus leaves every 6 minutes and another leaves every 9 minutes. The two buses leave together at the start of the day. Work out how long it is until they next leave together.
(a)18 minutes
(b)54 minutes
(c)3 minutes
(d)15 minutes
7.Work out how many factors 36 has.
(a)5
(b)10
(c)8
(d)9
8.Work out the highest common factor of 20 and 32.
(a)8
(b)4
(c)2
(d)160
9.A gardener has 42 tulip bulbs and 56 daffodil bulbs. She plants them in rows, with every row containing the same number of tulip bulbs and the same number of daffodil bulbs, and no bulbs left over. Work out the greatest number of rows she can plant.
(a)7
(b)14
(c)2
(d)168
10.Is 120 divisible by 5? Give a reason for your answer.
(a)Yes, because 120 ends in 0
(b)No, because 1 + 2 + 0 = 3 is not a multiple of 5
(c)Yes, because 120 is even
(d)No, because 5 does not divide into 12
11.Which of these numbers is a common factor of 18 and 24?
(a)6
(b)8
(c)12
(d)9
12.Work out the highest common factor of 15 and 25.
(a)75
(b)5
(c)15
(d)3
13.Work out 2 × 3 × 5 + 1 and decide whether the result is a prime number.
(a)30, which is not prime
(b)31, which is not prime because 31 = 1 × 31
(c)31, which is not prime because it is a multiple of 3
(d)31, which is prime
14.Write 12 as a product of its prime factors.
(a)2² × 3
(b)2 × 3²
(c)2 × 3
(d)2 × 6
15.Which statement about the number 51 is correct?
(a)51 is prime, because it is not divisible by 2, 3 or 5.
(b)51 is not prime, because it is divisible by 2.
(c)51 is prime, because it is an odd number.
(d)51 is not prime, because 51 = 3 × 17.

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