Percentage Trick - Solve precentages mentally - percentages made easy with the cool math trick!
TLDRIn this video, viewers learn a simple and effective mental math trick for calculating percentages quickly. The video starts with easy percentages like 15%, 25%, and 50%, using straightforward concepts like dividing by 10 or 2 to break down percentages. As the tutorial progresses, the host explains how to calculate more complex percentages mentally by breaking them into simpler parts (like 10% and 5%) and adding or subtracting. The video concludes by challenging viewers with examples to practice these skills and promises more advanced calculations in future lessons.
Takeaways
- 📊 Percentages are numbers out of 100, with 'per' meaning 'out of' and 'cent' meaning '100'.
- 🔢 To find percentages mentally, break them down into easy components like 50%, 10%, and 5% of a number.
- ✂️ 50% is half of a number, while 10% is found by moving the decimal one place to the left.
- 🧮 5% is simply half of 10%, which makes it quick to calculate in your head.
- 💡 For 15%, calculate 10% and 5%, then add them together. Example: 10% of 80 is 8, 5% is 4, so 15% is 12.
- 📝 More complex percentages like 95% can be broken down by subtracting 5% from the total (100%).
- ⚡ Practice is essential to get faster at these mental calculations, and over time you will improve.
- 📏 A trick for 25% is to think of it as dividing the number by 4, making calculations easier.
- 🔍 For larger percentages like 85%, subtract 10% and 5% from the total to get the final answer.
- 📈 Future videos will focus on more complex percentages like 22%, 53%, and 87%, moving beyond simple fives and tens.
Q & A
What is the primary focus of the video?
-The video focuses on teaching how to solve percentages mentally, starting with simple percentages like 15%, 25%, 50%, 75%, and 95%, using easy techniques.
How does the presenter define 'percentage'?
-The presenter explains that 'percentage' is a number out of 100. 'Per' means 'out of,' and 'cent' means '100'.
What is 100% of a number?
-100% of a number is the number itself. For example, 100% of 80 is 80.
How do you calculate 50% of a number?
-50% of a number is half of that number. For example, 50% of 80 is 40.
How is 10% of a number calculated?
-To calculate 10% of a number, you divide the number by 10 or move the decimal place one position to the left. For example, 10% of 80 is 8.
What is the trick for calculating 5% of a number?
-5% of a number is half of 10%. For example, 5% of 80 is 4.
How can you calculate 15% of a number?
-To calculate 15%, first find 10% and 5%, then add them together. For example, 10% of 80 is 8, and 5% is 4, so 15% of 80 is 12.
How do you calculate 60% of a number mentally?
-To calculate 60%, break it into 50% and 10%. For example, 50% of 42 is 21, and 10% of 42 is 4.2. Adding these gives 25.2.
What approach is suggested for calculating 95% of a number?
-For 95%, calculate 100% and subtract 5%. For example, 100% of 720 is 720, and 5% is 36. Subtracting 36 from 720 gives 684.
What is the method for calculating 85% of a number?
-To calculate 85%, subtract 15% from the number. For example, find 10% (62) and 5% (31) of 620. Subtracting these from 620 gives 527.
Outlines
📊 Introduction to Quick Percentage Calculation
This paragraph introduces the topic of calculating percentages in your head, focusing on simple percentages like 15%, 25%, 50%, and 95%. It explains that the video will start with basic examples before moving on to more complex ones. The host emphasizes that percentages represent 'out of 100' and provides a quick example of calculating 15% of 80, arriving at 12.
🔢 Breaking Down Percentage Calculations
This section explains how to calculate percentages like 100%, 50%, 10%, and 5% of a number by showing examples. It walks through the method of determining 10% by moving the decimal and calculating 5% as half of 10%. The explanation covers how 15% of 80 can be calculated by combining 10% (8) and 5% (4) to get 12. It also offers a more complex example, showing how to calculate 60% of 42 by combining 50% (21) and 10% (4.2), totaling 25.2.
🧮 Handling 95% and Complex Percentages
The paragraph discusses calculating 95% of a number, using 720 as an example. By subtracting 5% (36) from 720, the result is 694. The section encourages viewers to practice with several examples like 55% of 360 and 25% of 860, emphasizing mental calculation strategies such as breaking down percentages into smaller, manageable parts.
🤓 Practice with More Challenging Percentages
This part presents three more practice problems: calculating 55%, 25%, and 85% of various numbers. The host demonstrates the mental steps involved, such as dividing numbers by half for 50% or by four for 25%. For example, 25% of 860 is calculated as 215 by dividing by four, and 85% of 620 is calculated by subtracting 10% (62) and 5% (31) from 620, resulting in 527.
📝 Preparing for More Complex Percentages
The final paragraph summarizes the benefits of practicing mental percentage calculations. It emphasizes that the next video will tackle more complex percentages like 22%, 53%, and 87%. The host encourages viewers to continue practicing and mastering mental math with more advanced percentages.
Mindmap
Keywords
💡Percentage
💡Mental Calculation
💡10%
💡50%
💡5%
💡15%
💡100%
💡Decimal Shifting
💡Subtracting Percentages
💡Practice
Highlights
Introduction to mental percentage calculations.
Focus on simple percentages involving 5%, 10%, 25%, 50%, 75%, and 95%.
Explanation of the meaning of percentage, where 'per' means out of and 'cent' means 100.
Key tip: 100% of a number is the number itself.
50% of a number is half of the number.
10% of a number is found by dividing the number by 10.
5% of a number is half of 10%.
Example calculation: 15% of 80 is 12, by adding 10% (8) and 5% (4).
Example of 60% of 42, calculated as 50% (half of 42 = 21) plus 10% (moving the decimal = 4.2), adding up to 25.2.
Example of calculating 95% of 720 by subtracting 5% from 100%, resulting in 694.
Encouragement to practice mental calculations for fluency.
Detailed breakdown of how to calculate 55%, 25%, and 85% of various numbers.
Explanation of how to break down 85% into 100%, minus 10%, minus 5%.
Practice exercises included for viewers to pause the video and solve.
Preview of next video covering more complex percentages like 22%, 53%, and 87%.