Number worksheet — GCSE Foundation

1.A school orders 187 packed lunches for a trip. Each packed lunch costs £4.85. The school has £900 to spend. By rounding each number to 1 significant figure, work out an estimate for the total cost and decide whether £900 is enough.

2.Light travels at 2.998 × 10⁸ metres per second. A distant object in space is 3.1 × 10¹⁵ metres from Earth. Work out an estimate for the number of seconds light takes to travel from the object to Earth, by rounding each number to 1 significant figure.

3.A garden has flowers, herbs and vegetables in the ratio 2 : 3 : 4. What fraction of the garden is not vegetables?

4.The thickness of a sheet of card is 0.02384 cm. Write this thickness correct to 2 significant figures.

5.A spreadsheet shows that 812 − 397 = 315. Work out an estimate for 812 − 397, by rounding each number to the nearest 100, to check whether the spreadsheet's answer is reasonable.

6.A shop assistant says that 7.2 × 3.9 = 56.16. Work out an estimate for 7.2 × 3.9, by rounding each number to the nearest whole number, to show that the assistant’s answer cannot be correct.

7.Work out the reciprocal of (2 + 3)

8.The number 72 can be written as 2³ × 3², and the number 108 can be written as 2² × 3³. Work out the highest common factor of 72 and 108.

9.Write down the symbol that makes this statement true: −9 ___ −4

10.Write 0.06 as a fraction in its simplest form.

11.Work out −7 − (−3).

12.Write these three numbers in order of size, starting with the smallest: 0.7, 3/4, 0.72

13.A tin of paint has a mass of 5.672 kg. Round this mass to 1 decimal place.

14.A cinema has 21 rows of seats with 29 seats in each row. Work out an estimate for the number of people the cinema can hold, by rounding each number to 1 significant figure.

15.Work out (5 + 2) × 3²