IGCSE Unit 1 Chapter 1 Summary questions

Here is a set of numbers: {−4, −1, 0, 3, 4, 6, 9, 15, 16, 19, 20} Which of these numbers are natural numbers?

• −4, −1, 0, 3, 4, 6, 9, 15, 16, 19, 20

• 3, 4, 6, 9, 15, 16, 19, 20

• −4, −1, 0

• 4, 9, 16

Answer explanation

Natural number: Any whole number from 1 to infinity, sometimes called ‘counting numbers’. 0 is not included. 1, 2, 3, 4, 5, . . .

Here is a set of numbers: {−4, −1, 0, 3, 4, 6, 9, 15, 16, 19, 20} Which of these numbers are prime numbers?

• −4, −1, 0, 3, 4, 6, 9,

• -1, 3, 9, 15, 19

• 3, 9, 19

• 3, 19

Here is a set of numbers: {−4, −1, 0, 3, 4, 6, 9, 15, 16, 19, 20} Which of these numbers are multiples of two ?

• 4, 6, 16, 20

• -4, 0, 4, 6, 16, 20

• 0, 4, 6, 16, 20

• 4, 9, 16

Answer explanation

Natural number: Any whole number from 1 to infinity, sometimes called ‘counting numbers’. 0 is not included. 1, 2, 3, 4, 5, . . .

Here is a set of numbers: {−4, −1, 0, 3, 4, 6, 9, 15, 16, 19, 20} Which of these numbers are square numbers?

• −4, −1, 0, 3, 4, 6, 9, 15, 16, 19, 20

• 3, 4, 6, 9, 15, 16, 19, 20

• −4, −1, 0

• 4, 9, 16

Here is a set of numbers: {−4, −1, 0, 3, 4, 6, 9, 15, 16, 19, 20} Which of these numbers are negative integers?

• −4, −1, 0, 3, 4, 6, 9, 15, 16, 19, 20

• 3, 4, 6, 9, 15, 16, 19, 20

• −4, −1,

• −4, −1, 0

Find the HCF of 64 and 144

• 4

• 16

• 576

• 9216

List the first five multiples of 12

• 1, 12, 24, 36, 48

• 1, 2, 3, 4, 6, 12

• 12, 24, 36, 48, 60

• 60

Find the LCM of 24 and 36.

• 12

• 6

• 72

• 48

• 52

• 17576

• 13

• 676

• 14.3

• 79507

• 129

• 1849