Number (higher)

Question 1

A pile of paper is 6cm high. Each sheet is 0.008cm thick. How many sheets are there in the pile of paper?

Answer 1

6 ÷ 0.008 = 750

So there are 750 pages in the pile.

Question 2

Round the following numbers to the number of significant figures indicated.

a) 4078 (3 sf)
b) 0.006532 (1sf)
c) 34.78 (2sf)

Answer 2

a) 4080
b) 0.007
c) 35

Question 3

Henry has enough money to buy 14 bars of chocolate. Each bar of chocolate costs 35p. When Henry gets to the shop he finds that the price of a bar has risen to 40p. How many bars can he now buy?

Answer 3

Henry has 14 x 35 = 490p

490 ÷ 40 = 12.25

Henry can now buy 12 bars of chocolate

Question 4

What is the square root of 169?

Answer 4

13 or -13

Question 5

What is the HCF (Highest Common Factor) of 42 and 63?

Answer 5

Factors of 42: 1, 42, 2, 21, 3, 14, 6, 7

Factors of 63: 1, 63, 3, 21, 7, 9

So the HCF is 21.

Question 6

Work out

-3 + (2 – 5)

Answer 6

-3 – 3 = -6

Question 7

Express 72 as the product of its prime factors

Answer 7

72 = 2 x 2 x 2 x 3 x 3 = 2³ x 3²

Question 8

What is the LCM (lowest common multiple) of 15 and 25?

Answer 8

Multiples of 15: 15, 30, 45, 60, 75, 90, …

Multiples of 25: 25, 50, 75, 100, …

So the LCM is 75

Question 9

Find an approximate answer to

(574 – 247) ÷ 0.23

Answer 9

(600 – 200) ÷ 0.2

=400 ÷ 0.2

=2000

Question 10

Helen buys a laptop. She pays 10% of the cash price and then 24 monthly payments of £18. In total she pays £472. How much was the cash price of the laptop?

Answer 10

24 x 18 = 432

472 – 432 =40

£40 is 10% of cash price.

Cash price = 40 x 10 = £400