IGCSE MATHS CH1 - Numbers

What is a prime number?

• A number with 1 factor
• A number with 2 factors
• A number with 3 factors
• 2 factors (1 and itself)

Which factors prove that 29 is a prime number?

• 2, 29
• 1, 29
• 1, 2, 13, 29
• 29

Tags

CCSS.4.OA.B.4

Why is 15 not a prime number?

• 3x5
• 2x5
• 3x15
• 10+5

2 x 2 x 2 is the prime factorisation of

• 6

• 12

• 22

• 8

Which is the prime factorisation of 12?

• 2 x 6

• 2 + 2 + 2 + 2 + 2 + 2

• 2 x 2 x 3

• 1 x 2 x 2 x 3

Use a number tree to find the prime factorisation of 105

• 7x5x3

• 11x5x3

• 7x5x2x1

• 7x5x3x2

Find the HCF of 21 and 28

• 3
• 4
• 7
• 14

Tags

CCSS.6.NS.B.4

What is the LCM of 4 and 12? 

• 4
• 8
• 12
• 16

Tags

CCSS.6.NS.B.4

Find the HCF of 12 and 15 ?

• 2
• 2 x 3
• 3
• 60

Tags

CCSS.6.NS.B.4

Find the HCF of 40 and 60?

• 10
• 20
• 30
• None of the above

Tags

CCSS.6.NS.B.4