Fractions, Decimal And Percentages
Overview
A shop advertises 20 per cent off. A bank offers 4 per cent a year. A report says prices rose by 130 per cent. Three sentences, three completely different pieces of arithmetic, and the marks in this topic go to the candidate who can tell instantly which one is in front of them. Fractions, decimals and percentages are three notations for the same idea, and the fastest route through almost every question here is to convert to whichever of the three makes the calculation shortest.
You will convert freely between the three forms, use each of them as an operator that acts on a quantity, express one quantity as a fraction or a percentage of another even when the answer is greater than 1 or greater than 100 per cent, and handle percentage increase and decrease, simple interest and compound interest. On the Extension Tier you will also convert a recurring decimal into an exact fraction, solve reverse percentage problems where the figure you are given is the answer rather than the start, and use the compound interest formula the specification prints in full.
Objectives
- [Core] understand and use equivalent fractions, understand and use percentages, convert between fractions, terminating decimals and percentages
- [Extension] convert between fractions and recurring decimals
- [Core] interpret fractions, decimals and percentages as operators
- [Core] express one quantity as a fraction/percentage of another, where the fraction is less than 1 or greater than 1 or the percentage is less than 100 or greater than 100
- [Core] solve problems involving percentage change, including increase/decrease, simple interest and compound interest
- [Extension] reverse percentage problems
- [Extension] knowledge and use of the compound interest formula value of investment = P(1 + r/100)ⁿ where P is the amount invested, r is the percentage rate of interest and n is the number of years of compound interest
Mind map
This topic is mapped out so you can see how the ideas connect.
Open the mind map in the app
Lesson Note
Complete Note Available on the Green Bridge App
Get the Green Bridge CBT app on your phone or computer for the complete IGCSE library: past papers, mark schemes, mind maps, flashcards and audio lessons.
Lesson Evaluation
Congratulations on completing the lesson on Fractions, Decimal And Percentages. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Circle the percentage that is more than one quarter and less than one half. A. 15% B. 20% C. 35% D. 55% Answer: C
- Which multiplier increases a quantity by 130 per cent? A. 0.30 B. 1.30 C. 2.30 D. 130 Answer: C
- Which of these fractions gives a terminating decimal? A. 4/15 B. 5/11 C. 2/7 D. 9/16 Answer: D
- A price is reduced by 10 per cent and then increased by 10 per cent. Compared with the original price, the final price is A. the same B. 1 per cent lower C. 1 per cent higher D. 10 per cent lower Answer: B
- A price including 20 per cent sales tax is $54. What was the price before tax? A. $43.20 B. $45.00 C. $45.90 D. $64.80 Answer: B
Work through these questions in the app
Work through these questions in the app
Recommended Books
Practice Mock Questions
Want to practice mock questions on Fractions, Decimal And Percentages? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.
Download The App On Google Playstore
Everything you need to excel in your exams
