# Ingenious Math Trick Allows You to Easily Calculate Percentages in Your Head

Stock Photos from ImageFlow/Shutterstock

If you struggle with math, the idea of calculating percentages will probably send you into a mild panic. However, thanks to the wisdom of self-confessed “maths whizz” Ben Stephens, it might be easier than you think. Stephens recently tweeted a mind-blowing math trick on how to calculate percentages in your head. His surprisingly simple solution has now gone viral and left a lot of people wondering why it wasn’t taught at school.

So what’s the secret formula? It’s simple: x% of y = y% of x. Stephens explains, “So, for example, if you needed to work out 4% of 75 in your head, just flip it and and do 75% of 4, which is easier.” If you haven’t already worked it out, the answer is 3, and the easy trick can be applied to any set of numbers. “18% of 50 feels hard to calculate,” Stephens tweeted. “But 50% of 18 is a doddle, right?” You got it—9!

Most people on Twitter reacted gratefully to Stephens’ revealing method, and some even asked if he could tutor them. “I am neither a math guy nor a teacher,” he writes. “I just learned this and thought it was cool, so I decided to share it on Twitter, and it seems to have become one of my most popular tweets ever.”

Try this new method out for yourself and see more from Stephens’ mental math conversions on Twitter.

## His surprisingly simple solution has now gone viral and left a lot of people wondering why it wasn’t taught at school.

h/t [IFL Science!]

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### Emma Taggart

Emma Taggart is a Contributing Writer at My Modern Met. Originally from Northern Ireland, she is an artist now based in Berlin. After graduating with a BA in Fashion and Textile Design in 2013, Emma decided to combine her love of art with her passion for writing. Emma has contributed to various art and culture publications, with an aim to promote and share the work of inspiring modern creatives. While she writes every day, she’s also devoted to her own creative outlet—Emma hand-draws illustrations and is currently learning 2D animation.
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