Multiples
Factors
Primes
HCF & LCM
100
List the first five multiples of 3
3, 6, 9, 12, 15
100
Find a factor of 33 that is between 10 and 20
11
100
List all of the prime numbers between 10 and 20.
11, 13, 17, 19
100
What is the highest common factor of 8 and 20
4
200
List all multiples of 2 between 35 and 45
36, 38, 40, 42, 44
200
Find a factor of 75 between 20 and 30
25
200
What is the 6th prime number?
13
200
Find the lowest common multiple of 4 and 10
20
300
What is the first even multiple of 9?
18
300
What is the largest factor of 158?
158
300
Explain why 21 is not a prime number
21 has more than 2 factors
300
1155
400
True of False:
All multiples of 3 are odd
False
400
List all factors of 18
1, 2, 3, 6, 9, 18
400
Write 30 as a product of its prime factors.
2\times 3\times5
400
14
500
Mr Knox says "All multiples of a number are larger than the number".
Give an example to show that Mr Knox is wrong.
Many answers, e.g. 5 is a multiple of 5
500
Mr Knox says "The larger a number is, the more factors it has."
Give an example to show Mr Knox is wrong.
Many answers e.g. 6 has more factors than 7
500
Write 108 as a product of its prime factors.
2^2\times 3^3
500
A bell rings every 12 minutes.
A light flashes every 9 minutes.
At 8:00 pm, the bell rings and the light flashes at the same time.
Work out the next time at which the bell will ring and the light will flash together.
LCM = 36
so the answer is 8:36 pm