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Percentages are everywhere. Whether you’re shopping for a new car, trying to figure out how much tax you need to pay on your income, or comparing two different numbers, percentages are a big part of the equation. But calculating percentages can be intimidating if it’s something you’re not used to doing. Thankfully, there is an easy method that anyone can use to quickly calculate percentages in their head. In this blog post, we will look at a step-by-step guide on how to do this and make calculations with ease.
What is a percentage?
A percentage is a way of expressing a number as a fraction of 100. It is often denoted using the percent sign, “%”, or the abbreviations “pct.”, “pct”; sometimes the abbreviation “pc” is also used. A percentage is a dimensionless number (pure number); it has no unit of measurement.
Basic percentage calculation
When it comes to quick percentage calculation, the first thing you need to do is identify the number that represents the whole. This is usually represented by 100%, and so in order to calculate a percentage, you need to divide the number you’re interested in by 100. For example, if you wanted to find 19% of 120, you would divide 120 by 100 to get 1.2, and then multiply 1.2 by 19 to get 22.8.
It’s important to note that when working with percentages, you always need to use a common base. In other words, if you’re given two numbers and asked to find the percentage of one number with respect to the other, you need to make sure that both numbers are expressed as a percentage of the same thing. For example, let’s say you’re asked to find 50% of 80. You might be tempted to just divide 80 by 50 to get 1.6, but this would be incorrect because 50% and 80% are not both percentages of the same thing – 50% is a percentage of 100%, whereas 80% is a percentage of something else entirely.
To correctly solve this problem, you would first need to express both numbers as percentages of the same base – in this case, 100%. To do this, simply divide both numbers by 100: 50% becomes 0.5 and 80% becomes 0.8. Now that they’re both percentages of 100%, you can safely divide 0.8 by
How to calculate percentages in your head
Whether you’re trying to save money on a purchase or make sure you’re getting the most bang for your buck on a sale, being able to calculate percentages in your head is a valuable skill. Here’s a step-by-step guide to quickly calculating percentages without breaking out the calculator:
1. To start, you’ll need to know what percentage you’re looking for. Let’s say you want to find 20%.
2. The next step is to move the decimal point two places to the left. So, 20% would become 0.20.
3. Once you have your number in decimal form, simply multiply it by the whole number you’re working with. So, if you’re trying to find 20% of 100, you would multiply 0.20 by 100 which would give you 20.
Tips and tricks for quickly calculating percentages
If you find yourself needing to calculate percentages on the fly, there are a few tricks you can use to quickly come up with an accurate answer.
To start, let’s say you want to find 19% of $50. You can use the following shortcut:
First, divide the number by 10 to get 5. Then, multiply that by 2 to get 10. Add the two numbers together, and finally add a 0 to the end (19% = 10 + 9). So in this case, 19% of $50 would be $10 + $9, or $19.
Here’s another example: what’s 32% of $40? Again, divide by 10 and multiply by 2, which gives us 8. But this time, we need to subtract the answer from the original number (32% = 40 – 8). So 32% of $40 would be $40 – $8, or $32.
You can also use this trick for calculating percentage increase or decrease. For instance, let’s say you want to know how much more money you’ll have if your salary is increased by 3%. First, take 3% of your salary (3% = 0.03 x salary) and then add it to your salary. So if your salary is currently $50,000 per year, your new salary after a 3% raise would be ($50,000 x 0.03) + $50,000 = $51,500
More complex percentage calculations
More complex percentage calculations can be a bit tricky, but with a little practice, you’ll be able to do them quickly and easily. Here are a few tips:
To calculate a percentage of a whole, divide the number you want to find the percentage of by the total number, and then multiply by 100. For example, if you want to find 10% of 100, you would divide 10 by 100, which equals 0.1. Then, multiply 0.1 by 100 to get 10%.
To calculate a percentage of a part, divide the number you want to find the percentage of by the total number, and then multiply by the part’s percentage. For example, if you want to find 10% of 50%, you would first divide 10 by 50 (which equals 0.2), and then multiply 0.2 by 50% (which equals 10%).
You can also use percentages to calculate how much something has increased or decreased. To do this, take the original value and subtract it from the new value. Then, divide this difference by the original value and multiply by 100. For example, if something has increased from 10 to 20, you would first subtract 10 from 20 (which equals 10). Then, divide 10 by 10 (which equals 1), and then multiply 1 by 100 (which equals 100%). This means that the thing has increased by 100%.
When to use a calculator
There are certain situations where it makes sense to use a calculator to calculate percentages. For example, when you need an accurate result and time is not a factor, or when the numbers involved are very large.
If you’re just trying to estimate a percentage, though, there’s no need to use a calculator. With a little practice, you can learn how to do it quickly in your head. Here’s a step-by-step guide:
1. Estimate the whole number that the percentage corresponds to. For example, if you’re trying to find 10% of 100, you can round 100 down to 90.
2. Multiply that number by the percentage you’re trying to find (in this case, 10). So 90 x 10 = 900.
3. To get the final answer, move the decimal point two places to the left. In this case, 900 becomes 9.00 or simply 9 (since we rounded down in step 1).
So 10% of 100 is approximately 9. You can use this method for any percentage and any whole number – just make sure to do the math quickly in your head!
Conclusion
We hope this guide has given you a good understanding of the different methods for quickly calculating percentages in your head. It takes practice to master these techniques, but once you’ve got them down, you’ll find that it’s much easier to do mental math with percentages than without. With the help of this guide, you can now impress friends and colleagues alike with your newfound skills!
