Magic and tricks with maths

The mathematical trick to make calculations more easily than it went viral (and that nobody taught us in school)

Do you also run for the calculator every time you have to calculate a percentage? Well, advertising editor Ben Stephens posted on Twitter a trick you wish you had known all your life.

The ingenious formula proposed by the tweet to calculate percentages is the following: x% of y = y% of x.

Thus, following the example of Stephens, 4% of 75 is equal to 75% of 4, with the difference that investing the numbers is much easier to calculate. The answer, in this case, is 3.

Let's do another test. It is likely that it will be difficult for you to calculate mentally and with speed 18% of 50. But applying the formula that Stephens viralized, we know that 18% of 50 equals 50% of 18. And 50% of 18 is 9, much easier to calculate, right?

The tweet already has almost 6,500 retweets and more than 18,000 likes.

In another post, Stephens himself acknowledged that he did not expect it to go viral: "Typical, I spend years tweeting about important things about Trump and Brexit, and then I publish a tweet about mathematics (a topic I had never tweeted before) and the internet goes crazy. "

Many users of the social network thanked him for discovering a trick that they say will be useful to them.

BBC: "El truco matemático para hacer cálculos más fácilmente que se hizo viral (y que nadie nos enseñó en la escuela)" (12 de marzo de 2019). Extraído de: https://www.bbc.com/mundo/noticias-47540941