Lemmara logoLemmaraWorked solution

4024/23 May/Jun 2025, Question 13: Standard Form

Cambridge O Level Mathematics 4024 · Paper 23 (Calculator) · Calculator · 3 marks

اقرأ هذا الحل مشروحاً بالعربي ←

The question, in short

Convert a small standard form number to an ordinary decimal, then find x and y so the sum of two standard form terms equals 9.1 × 10⁵.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Part (a) · 1 mark

Write 1.23 × 10⁻⁴ as an ordinary decimal number.

  1. 1Move the decimal point 4 places left
  2. 21.23 × 10⁻⁴ = 0.000123

Answer0.000123

Part (b) · 2 marks

Given (8.2 × 10⁴) + (x × 10ʸ) = 9.1 × 10⁵, find the values of x and y.

  1. 1x × 10ʸ = 9.1 × 10⁵ − 8.2 × 10⁴
  2. 2= 910000 − 82000 = 828000
  3. 3= 8.28 × 10⁵
  4. 4x = 8.28, y = 5

Answerx = 8.28, y = 5

Stuck on a step? Read the free lesson: Standard Form

Practise more standard form questions

Real 4024 past-paper questions, marked on your working like the exam, with a worked solution for every part.

Practise free on Lemmara

More past-paper questions on standard form

Also searched as: 4024/23/M/J/25 · 4024_s25_qp_23 · 4024 s25 23 · question 13.
Lemmara is an independent study tool, not affiliated with or endorsed by Cambridge International Education. The worked solutions are Lemmara’s own.