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.For any two whole numbers, the product of the numbers is equal to the product of their highest common factor and their lowest common multiple. The highest common factor of 6 and 8 is 2, and 6 × 8 = 48. Work out the lowest common multiple of 6 and 8.
(a)24
(b)12
(c)48
(d)96
2.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
3.The number 72 can be written as 2³ × 3², and the number 108 can be written as 2² × 3³. Work out the highest common factor of 72 and 108.
(a)36
(b)6
(c)108
(d)216
4.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
5.Work out the highest common factor of 12 and 18.
(a)2
(b)6
(c)36
(d)3
6.Work out the highest common factor of 20 and 32.
(a)8
(b)4
(c)2
(d)160
7.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
8.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
9.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.
10.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.
11.Work out the highest common factor of 15 and 25.
(a)75
(b)5
(c)15
(d)3
12.Work out the lowest common multiple of 4 and 6.
(a)12
(b)2
(c)6
(d)24
13.Write down a prime number between 30 and 40.
(a)33
(b)31
(c)36
(d)34
14.Write 60 as a product of its prime factors, using index notation.
(a)2 × 3 × 5
(b)2² × 3 × 5
(c)2 × 3 × 5²
(d)2² × 3² × 5
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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