Primes/Prime factorisation
What is a Prime number?
A number with exactly two factors
Calculate 3 + 5 x 2
13
If 8 x 2 is 16, what is 8 x 20?
160
What is the 6th multiple of 12?
72
What is a factor and can you give an example
A number that divides into another number exactly, leaving no remainder e.g. 12 is a factor of 24
No, as it has more than two factors
5 x 3 and 15 x 1
7
If 24 x 12 = 288. What is 24 x 1.2?
28.8
What are the first 3 common multiples of 4 and 6?
12, 24 and 36
What are the factors of 18?
1 and 18
2 and 9
3 and 6
What are the prime numbers between 10 and 20?
11, 13, 17 and 19
Calculate 2 + 62 - 5 x 3
23
If 14 x 16 = 224. What is 7 x 32 =
Can you explain how you know
224
What is the lowest common multiple of 10 and 15?
30
What is the highest common factor of 12 and 18?
6
Break 24 down into a product of its prime factors
2 x 2 x 2 x 3 or 2 cubed x 3
If 28 x 56 = 1568. What is the answer to 14 x 112?
Can you explain how you know?
1568
If a number is a multiple of 12. What other numbers must it also be a multiple of?
1,2,3,4,6 as these are all factors of 12
What is the Highest common factor of 18 and 54?
18
Break 50 down into a product of its prime factors
2 x 5 x 5 or 52 x 2
Calculate 5 + 2 x 100 - 62
169
If 35 x 0.5 = 17.5 What is 70 x 0.25
Can you explain how you know?
17.5
One traffic light changes every 8 seconds. A different traffic light changes every 10 seconds. After how long will they change at the same time.
40 seconds
Two wires are 45 metres and 108 metres long. They need to be cut into pieces of equal length. Find the maximum length of each piece?
9 metres