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67
“This Changed My Life”: People React To Math Hack To Easily Calculate Percentages
Many of us have hardly retained anything from our school years, especially mathematics classes.
Therefore, it does not come as a surprise that adults tend to use their phone calculators to compute the most basic additions and subtractions.
But one calculator feature, which people might especially enjoy upon shopping during sales, is to be able to deduce a percentage off a number.
Highlights
- Adults often use phones for basic math, highlighting reliance on technology.
- Selina's video shares a math hack for calculating percentages without a calculator.
- Divide both numbers by 10, then multiply to find percentages easily.
- Example: 40% of 30 is calculated as 4x3, resulting in 12.
However, on the off and scary chance that one might find themselves devoid of their smartphones during Black Friday shopping for Christmas gifts, being able to calculate a percentage is undeniably a good skill to have.
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A math hack has been circulating online that helps calculate percentages in an easier way
Image credits: gunsnrosesgirl3
Image credits: gunsnrosesgirl3
Selina, who runs the popular science-themed “gunsnrosesgirl3” X (formerly known as Twitter) account, shared a video on Monday (November 20) that could potentially revolutionize the way people calculate percentages.
One of the better-known methods to calculate percentages is to simply multiply the starting number by the percentage number as a fraction.
You can take a look at the simple method below
How to easily work out percentages
pic.twitter.com/rQbPF3fKl3— Science girl (@gunsnrosesgirl3) November 20, 2023
Image credits: Annie Spratt
Nevertheless, this method once again might often require the use of a calculator, for those who would identify themselves as not being the most mathematically knowledgeable people.
As a result, Selina’s video, which has been viewed 11.8 million times, exposes an easy hack to get around percentages.
You simply need to divide two numbers by ten and then multiply them by each other
Image credits: Joshua Hoehne
It demonstrates that you would simply need to divide two numbers by ten and then multiply them by each other.
As a result, it would look like this following example: 40 percent of 30 is 4 x 3, which equals 12.
Unilad has demonstrated the calculation with the example of a restaurant bill amounting to $87.50.
To get the 20 percent for, for example, your tip, you calculate 2 x 8.75, which would equal a tip of $17.50.
For example: 40 percent of 30 is 4 x 3, which equals 12
Image credits: ThisIsEngineering
“Something as neat and efficient as this will never be taught in public education,” an X user commented.
A person tried to challenge other X users with the following problem: “Now do 41% of 30…” to which a person replied: “That should be 4.1 x 3 = 12.3?”
Image credits: Mikhail Nilov
The person who challenged fellow X users with the seemingly complicated request went on to congratulate the individual who took up the challenge and wrote: “Bingo! I don’t know why the video didn’t show how to do it with numbers that do not finish with 0.”
In other math news, a trend branded “girl math” has taken social media by storm, which has seen women posting their hilarious reasoning when shopping, packing, and saving time and money.
An example of girl math consists of not paying $15 in shipping, and instead spending another $30 in order to benefit from the free shipping.
Many people had never seen the method before
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Id row 2 years ago
It makes me sad that what was once common knowledge is now considered a newly discovered life hack.
Kobe (she) 2 years ago
Teaching a "hack " is only useful when the underlying principles are taught too - why it works. Otherwise, they will fail to answer slightly different phrased questions.
Load More Replies...
SadieCat17 (she/her) 2 years ago
The people in the comments trying to be rude to her for pointing out a neat trick smh. Of course it doesn't work for every number, but it's useful for things like sales or tipping where you see nice round numbers. Why is everyone being so aggressive??
Ace 2 years ago
I don't get it either. It's just multiplying one by the other and divide by 100, the only 'hack' element is that with two-digit multiples of ten you can just knock off the two zeros to do the division. Doesn't work so well though if you want to calculate 63% of 223, for example.
Load More Replies...
Apatheist Account2 2 years ago
*Boomer alert* so what are they teaching kids in school these days? Easy enough with multiples of ten, but what's 17.5% of 26,937? Oh, 1.75 * 2693.7? Do that in your head! My favourite "hack" for 17.5% by the way, courtesy of Carol Vorderman, is that it's 10% + 5% + 2.5% - so divide by 10, half it, half it again, then add those 3 together.
James Doe 2 years ago
Obvious, but very usefull. Split the 100 in the denominator into 10x10 and do those divisions first.. duh! I didn't consciously use this yet, and I'm an engineer from one of the most renown universities of the world.. Similarily obvious, yet many people don't know is that "%" isn't just a random symbol but is derived from "100" -> 1/100
Crazy Horses 2 years ago
I was taught this by a shop assistant when I was 15 when I asked her how she calculated the discounts so quickly. I really stuggled with Maths at school, but this made so much sense if you know how to apply it correctly.
Nizumi 2 years ago
I just tried to calculate 15% of $294 using this method. 1.5 x 29.4 = 30.9. But when I use a calculator and multiply 294 by .15 I get $44.1. So somewhere this doesn't work. What am I missing?
Apatheist Account2 2 years ago
You added instead of multiplying. 1.5+29.4=30.9.
Load More Replies... Id row 2 years ago
It makes me sad that what was once common knowledge is now considered a newly discovered life hack.
Kobe (she) 2 years ago
Teaching a "hack " is only useful when the underlying principles are taught too - why it works. Otherwise, they will fail to answer slightly different phrased questions.
Load More Replies... SadieCat17 (she/her) 2 years ago
The people in the comments trying to be rude to her for pointing out a neat trick smh. Of course it doesn't work for every number, but it's useful for things like sales or tipping where you see nice round numbers. Why is everyone being so aggressive??
Ace 2 years ago
I don't get it either. It's just multiplying one by the other and divide by 100, the only 'hack' element is that with two-digit multiples of ten you can just knock off the two zeros to do the division. Doesn't work so well though if you want to calculate 63% of 223, for example.
Load More Replies... Apatheist Account2 2 years ago
*Boomer alert* so what are they teaching kids in school these days? Easy enough with multiples of ten, but what's 17.5% of 26,937? Oh, 1.75 * 2693.7? Do that in your head! My favourite "hack" for 17.5% by the way, courtesy of Carol Vorderman, is that it's 10% + 5% + 2.5% - so divide by 10, half it, half it again, then add those 3 together.
James Doe 2 years ago
Obvious, but very usefull. Split the 100 in the denominator into 10x10 and do those divisions first.. duh! I didn't consciously use this yet, and I'm an engineer from one of the most renown universities of the world.. Similarily obvious, yet many people don't know is that "%" isn't just a random symbol but is derived from "100" -> 1/100
Crazy Horses 2 years ago
I was taught this by a shop assistant when I was 15 when I asked her how she calculated the discounts so quickly. I really stuggled with Maths at school, but this made so much sense if you know how to apply it correctly.
Nizumi 2 years ago
I just tried to calculate 15% of $294 using this method. 1.5 x 29.4 = 30.9. But when I use a calculator and multiply 294 by .15 I get $44.1. So somewhere this doesn't work. What am I missing?
Apatheist Account2 2 years ago
You added instead of multiplying. 1.5+29.4=30.9.
Load More Replies... You May Like
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