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 · Non-calculator · 15 questions

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1.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
2.Work out the highest common factor of 12 and 18.
(a)2
(b)6
(c)36
(d)3
3.Which statement about the number 91 is correct?
(a)91 is not prime, because 91 = 7 × 13.
(b)91 is prime, because it is not divisible by 2, 3 or 5.
(c)91 is not prime, because it is divisible by 3.
(d)91 is prime, because it is an odd number ending in 1.
4.Write 200 as a product of its prime factors, using index notation.
(a)2 × 5³
(b)2³ × 5
(c)2² × 5³
(d)2³ × 5²
5.A rectangular patio measures 90 cm by 120 cm. Ben wants to cover it exactly with identical square tiles, as large as possible, with no tiles cut. Work out the side length of the largest square tile he can use.
(a)30 cm
(b)360 cm
(c)15 cm
(d)10 cm
6.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
7.Priya has 24 red beads and 36 blue beads. She makes identical bracelets, using every bead and with none left over. Work out the greatest number of bracelets she can make.
(a)6
(b)72
(c)60
(d)12
8.The number 24 can be written as 2³ × 3, and the number 60 can be written as 2² × 3 × 5. Work out the lowest common multiple of 24 and 60.
(a)120
(b)12
(c)1440
(d)60
9.Work out the highest common factor of 20 and 32.
(a)8
(b)4
(c)2
(d)160
10.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
11.The highest common factor of two numbers is 4 and their lowest common multiple is 60. One of the numbers is 20. Work out the other number.
(a)12
(b)240
(c)16
(d)15
12.Which of these numbers is a common factor of 18 and 24?
(a)6
(b)8
(c)12
(d)9
13.Work out the lowest common multiple of 9 and 15.
(a)24
(b)45
(c)135
(d)3
14.The number 36 can be written as 2² × 3², and the number 84 can be written as 2² × 3 × 7. Work out the highest common factor of 36 and 84.
(a)12
(b)3
(c)6
(d)252
15.Write 90 as a product of its prime factors.
(a)2 × 3² × 5
(b)2 × 45
(c)2 × 3 × 15
(d)3 × 3 × 10

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