Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
Show all topics
1l the quest for political stability: germany, 1871-1991
Britain & the wider world: 1745 -1901
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
Show all topics
Maths
27 Nov 2025
750
4 pages
Itz Gamer Al 123 @itzgameral123_tyei
Percentages are everywhere in daily life - from test scores to shop discounts to bank interest rates. Understanding... Show more
Think of percentages as a way to express parts of 100 - that's literally what 'per cent' means! When you see 25%, it's the same as saying 25 out of 100, or the fraction 25/100, or the decimal 0.25.
To find a percentage of any amount, you've got two straightforward methods. You can either convert the percentage to a fraction and multiply, or convert it to a decimal (16% becomes 0.16) and multiply. Both give you the same answer - pick whichever feels easier!
Here's a brilliant shortcut 10% of any number means dividing by 10. Once you know 10%, you can work out loads of other percentages. Need 5%? That's half of 10%. Need 30%? That's three times 10%. This method is often quicker than reaching for a calculator.
Quick Tip To find 10% of any number, just move the decimal point one place left. So 10% of 450 is 45.0!
When you need to increase or decrease an amount by a percentage, you can do it step by step or use the clever multiplier method. The step-by-step way means finding the percentage amount first, then adding or subtracting it from your original number.
The multiplier method is brilliant for calculator work and essential for compound interest problems. For a 15% increase, think "I'll have 115% total" (100% + 15%), which equals 1.15 as a decimal. For a 33% decrease, think "I'll have 67% left" (100% - 33%), which equals 0.67 as a decimal.
Expressing one number as a percentage of another is dead useful for test scores and comparing amounts. Just create a fraction and convert it so the bottom number is 100. If you scored 18 out of 20, that's 18/20 = 90/100 = 90%.
Calculator Shortcut To find one number as a percentage of another, divide the first by the second, then multiply by 100.
Percentage change helps you work out profit, loss, or any difference between two amounts. The formula is simple divide the difference by the original amount. If something costs £40 and sells for £50, that's £10 profit ÷ £40 original = 0.25 = 25% profit.
Reverse percentages are brilliant for working backwards from sale prices. Here's the key insight the original price is always 100%, no matter what it was. If a £24 top is marked down by 20%, then £24 represents 80% of the original price .
To solve reverse percentage problems, use the unitary method. If 80% = £24, then 1% = £24 ÷ 80 = £0.30, so 100% = £0.30 × 100 = £30. Always check your answer by working forwards!
Common Mistake Don't just add 20% of £24 to find the original price - that's not how percentages work when going backwards!
Simple interest is straightforward - you calculate the interest once and multiply by the number of years. Borrow £40 at 5% simple interest for 3 years? That's 5% of £40 = £2 per year, so £2 × 3 = £6 total interest.
Compound interest is where things get interesting (literally!). Each year, you earn interest on your interest too. Using the multiplier method makes this much easier - a 5% increase means multiplying by 1.05 each year.
For compound interest calculations over several years, you can use powers to save time. Instead of multiplying by 1.05 three separate times, just calculate £40 × 1.05³. This becomes essential when dealing with longer time periods.
Real-World Tip Banks use compound interest for savings accounts - that's how your money grows faster over time compared to simple interest!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
7
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential concepts of percentages, including calculations for simple and compound interest, percentage increase and decrease, and reverse percentages. This comprehensive guide provides step-by-step examples and practical applications to enhance your understanding and problem-solving skills. Ideal for students preparing for exams or seeking to improve their math proficiency.
MathsExplore key concepts of percentage calculations, including percent increase and decrease, through practical examples of depreciation and appreciation in property values. This summary covers essential calculations for Nat 5 Maths, helping students grasp the impact of percentages in real-life scenarios.
MathsExplore essential concepts in fractions, decimals, and percentages with this comprehensive knowledge organizer. Learn to convert numbers to standard form, perform percentage calculations, and understand key definitions like denominators and mixed numbers. Ideal for Year 10 students preparing for exams.
MathsExplore essential techniques for calculating percentages with this detailed guide. Learn how to find percentages of amounts, including step-by-step examples for 10%, 15%, and 32%. Ideal for WJEC Intermediate tier students, this resource emphasizes practical applications and accuracy in financial contexts.
MathsExplore the different types of angles including acute, right, obtuse, straight, and reflex angles. This summary also covers adjacent, complementary, and supplementary angles, detailing their measurements and relationships in geometry.
MathsComprehensive Edexcel Math Skills Checklist covering Geometry, Algebra, Statistics, and Probability for Grades 1-5. This resource includes essential concepts such as geometric shapes, data distributions, graphical representations, and key formulas. Perfect for students preparing for Edexcel assessments.
MathsApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Itz Gamer Al 123
@itzgameral123_tyei
Percentages are everywhere in daily life - from test scores to shop discounts to bank interest rates. Understanding how to work with percentages will help you calculate everything from your exam results to how much money you'll save in a... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Think of percentages as a way to express parts of 100 - that's literally what 'per cent' means! When you see 25%, it's the same as saying 25 out of 100, or the fraction 25/100, or the decimal 0.25.
To find a percentage of any amount, you've got two straightforward methods. You can either convert the percentage to a fraction and multiply, or convert it to a decimal (16% becomes 0.16) and multiply. Both give you the same answer - pick whichever feels easier!
Here's a brilliant shortcut: 10% of any number means dividing by 10. Once you know 10%, you can work out loads of other percentages. Need 5%? That's half of 10%. Need 30%? That's three times 10%. This method is often quicker than reaching for a calculator.
Quick Tip: To find 10% of any number, just move the decimal point one place left. So 10% of 450 is 45.0!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
When you need to increase or decrease an amount by a percentage, you can do it step by step or use the clever multiplier method. The step-by-step way means finding the percentage amount first, then adding or subtracting it from your original number.
The multiplier method is brilliant for calculator work and essential for compound interest problems. For a 15% increase, think "I'll have 115% total" (100% + 15%), which equals 1.15 as a decimal. For a 33% decrease, think "I'll have 67% left" (100% - 33%), which equals 0.67 as a decimal.
Expressing one number as a percentage of another is dead useful for test scores and comparing amounts. Just create a fraction and convert it so the bottom number is 100. If you scored 18 out of 20, that's 18/20 = 90/100 = 90%.
Calculator Shortcut: To find one number as a percentage of another, divide the first by the second, then multiply by 100.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Percentage change helps you work out profit, loss, or any difference between two amounts. The formula is simple: divide the difference by the original amount. If something costs £40 and sells for £50, that's £10 profit ÷ £40 original = 0.25 = 25% profit.
Reverse percentages are brilliant for working backwards from sale prices. Here's the key insight: the original price is always 100%, no matter what it was. If a £24 top is marked down by 20%, then £24 represents 80% of the original price .
To solve reverse percentage problems, use the unitary method. If 80% = £24, then 1% = £24 ÷ 80 = £0.30, so 100% = £0.30 × 100 = £30. Always check your answer by working forwards!
Common Mistake: Don't just add 20% of £24 to find the original price - that's not how percentages work when going backwards!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Simple interest is straightforward - you calculate the interest once and multiply by the number of years. Borrow £40 at 5% simple interest for 3 years? That's 5% of £40 = £2 per year, so £2 × 3 = £6 total interest.
Compound interest is where things get interesting (literally!). Each year, you earn interest on your interest too. Using the multiplier method makes this much easier - a 5% increase means multiplying by 1.05 each year.
For compound interest calculations over several years, you can use powers to save time. Instead of multiplying by 1.05 three separate times, just calculate £40 × 1.05³. This becomes essential when dealing with longer time periods.
Real-World Tip: Banks use compound interest for savings accounts - that's how your money grows faster over time compared to simple interest!
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
7
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential concepts of percentages, including calculations for simple and compound interest, percentage increase and decrease, and reverse percentages. This comprehensive guide provides step-by-step examples and practical applications to enhance your understanding and problem-solving skills. Ideal for students preparing for exams or seeking to improve their math proficiency.
MathsExplore key concepts of percentage calculations, including percent increase and decrease, through practical examples of depreciation and appreciation in property values. This summary covers essential calculations for Nat 5 Maths, helping students grasp the impact of percentages in real-life scenarios.
MathsExplore essential concepts in fractions, decimals, and percentages with this comprehensive knowledge organizer. Learn to convert numbers to standard form, perform percentage calculations, and understand key definitions like denominators and mixed numbers. Ideal for Year 10 students preparing for exams.
MathsExplore essential techniques for calculating percentages with this detailed guide. Learn how to find percentages of amounts, including step-by-step examples for 10%, 15%, and 32%. Ideal for WJEC Intermediate tier students, this resource emphasizes practical applications and accuracy in financial contexts.
MathsExplore the different types of angles including acute, right, obtuse, straight, and reflex angles. This summary also covers adjacent, complementary, and supplementary angles, detailing their measurements and relationships in geometry.
MathsComprehensive Edexcel Math Skills Checklist covering Geometry, Algebra, Statistics, and Probability for Grades 1-5. This resource includes essential concepts such as geometric shapes, data distributions, graphical representations, and key formulas. Perfect for students preparing for Edexcel assessments.
MathsApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
