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Factors, multiples and primes page 1 of 3

Factors, Multiples, Primes …. 1. Write down the next two multiples of 5

10, 15, 20, 25, ….., ….., 2. Write down the next three multiples of 7:

14, ……, ……, ……. 3. Write down the factors of 24:

{1, 2, ……, ……., …….,……., 12, …….,} 4. Write down the factors of 15:

{1, , 15} 5. Write down the first six prime numbers 6. Is 1 a prime? – Give a reason for your answer. 7. Is 127 a prime number?

Is it divisible by 2?

63.5

2 127 No

Is it divisible by 3? 3 127 ………

Is it divisible by …..? ……… Is it divisible by 7? ……… Is it divisible by …..? ……… So, 127 is/ isn’t a prime number

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Factors, multiples and primes page 2 of 3

8. Is 1957 a prime number? 9. Is 1951 a prime number?

10 (a) Express the 30 and 96 products of their prime factors. Complete

30

2 …….

3 ……..

Prime factors are: 2, 3 and …… .

96

2 …….

…….. ..……… ……… ……….. ……… ……….. ……… ………..

You may use any method you wish

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Factors, multiples and primes page 3 of 3

Prime factors are: 2, …., …., …., …., …… OR 2 × ……… (b) Find the Highest Common Factor of 30 and 96. Factors in common are: 2, and …… so the HCF = …….. × …….. = ………. (c) Work out the Lowest Common Multiple of 30 and 96.

LCM = 30 × 96 = ………… …………

10. Express 54 and 72 as product of primes, hence find the highest common factor of 54 and 72. 11. Find the highest common factor and the lowest common multiple of 108 and 180.