What are the first five multiples of 6?

6, 12, 18, 24, 30

What are the multiples of 9 between 60 and 80?

63 and 72

What is the lowest common multiple (LCM) of 6 and 8?

24

What is the lowest common multiple (LCM) of 7 and 5?

35

What is the lowest common multiple (LCM) of 10 and 15?

30

Sausages come in packs of 20. Bread rolls come in packs of 15. Bethany has an equal number of sausages and bread rolls. How many of each does she have?

60

What are the factors of 6?

1, 2, 3, 6

What are the factors of 24?

1, 2, 3, 4, 6, 8, 12, 24

What are the factors of 30?

1, 2, 3, 5, 6, 10, 15, 30

Give a factor of 16 that is not a factor of 12.

8 or 16

What is the highest common factor (HCF) of 12 and 18?

6

What is the highest common factor (HCF) of 24 and 20?

4

What is the highest common factor (HCF) of 60 and 45?

15

What is a prime number?

A number with exactly two factors: 1 and the number itself.

True or false:

1 is a prime number.

False

What is the first prime number?

2

What are the first ten prime numbers?

2, 3, 5, 7, 11, 13, 17, 19, 23, 29

Give two different prime numbers that add to 14.

3 and 11

Is 63 a prime number?

No

Give all the prime numbers between 70 and 80.

71, 73 and 79.

Write 60 as a product of its prime factors.

60 = 2^{3 }x 3 x 5

Write 1960 as a product of its prime factors.

1960 = 2^{3} x 5 x 7^{2}

a) Write 180 and 84 as a product of their prime factors.

b) Find the LCM of 180 and 84.

c) Find the HCF of 180 and 84.

a) 180 = 2^{2 }x 3^{2} x 5 and 84 = 2^{2} x 3 x 7

b) LCM = 1260

c) HCF = 12