Pearson Edexcel International GCSE (9–1) · MATHEMATICS A · Chapter
Number 2
18 practice questions
Practice questions
11–18 of 18
Question 11
3 marks · Normal
Answer and see the solution →Calculate (7.2 × 10^{-3}) ÷ (1.8 × 10^{2}) and give your answer in standard form.
Question 12
3 marks · Normal
Answer and see the solution →Copy and complete the table by writing each number in standard form.
Decimal Number Standard Form 720 000 0.082 6 301 000 Question 13
4 marks · Normal
Answer and see the solution →A scientific magazine gives the following information:
Diameter of objects Object Diameter (m) Dust particle 0.000 0031 Red blood cell 0.000 0072 Water molecule 0.000 000 27 (a)[1 mark]Write the diameter of the red blood cell in standard form.
(b)[1 mark]Express the diameter of the water molecule as an ordinary number.
(c)[2 marks]Calculate how many dust particles, placed end to end, would fit across the diameter of a red blood cell. Give your answer to 2 significant figures.
Question 14
2 marks · Normal
Answer and see the solution →Work out 10^{-2} × 10^7 and write your answer as a decimal.
Question 15
4 marks · Normal
Answer and see the solution →An engineer records the following readings for three components in a circuit:
Component Measurement A 4.5 × 10^{-2} B 7.3 × 10^{-1} C 2.8 × 10^1 (a)[1 mark]Write the value of component B as an ordinary number.
(b)[1 mark]Write the value of component C in standard form to 1 decimal place.
(c)[2 marks]Calculate the product of component A and component C. Write your answer in standard form.
Question 16
5 marks · Hard
Answer and see the solution →The distance from the Earth to Star X is 2.46 × 10^{12} km. The distance from the Earth to Star Y is 7.82 × 10^{13} km.
(a)[3 marks]Calculate how many times farther Star Y is from Earth compared to Star X. Give your answer in standard form.
(b)[2 marks]If a spaceship travels at 2.05 × 10^{5} km per hour, estimate how many hours it would take to reach Star X from Earth. Give your answer in standard form.
Question 17
4 marks · Hard
Answer and see the solution →Evaluate (4.8 \times 10^{-3}) \times (6.2 \times 10^{5}) and give your answer in standard form.
Question 18
6 marks · Hard
Answer and see the solution →A laboratory measures the masses of three specimens. Their masses are given below:
Specimen Mass (g) A 0.00741 B 0.0741 C 0.00417 (a)[3 marks]Write the mass of each specimen in standard form.
(b)[1 mark]Arrange the specimens in order of increasing mass.
(c)[2 marks]Calculate the difference in mass between specimen B and specimen C. Give your answer in standard form.