Simple method to work out complicated percentages is blowing people's minds

There's many things we spent hours learning in maths at school for one exam which we have never given a second thought to since.

For the majority of us, being able calculate the angle of a isosceles triangle or conquering algebra hasn't served us much use as we make our way through life.

One of the skills which hasn't proved completely useless is calculating percentages - but we can still struggle when the bill comes and we have to split it between five people while Carol argues that she didn't even have any of the prawn crackers.

Although we now all carry the calculator app in our pockets, it can still come in useful and a different way at looking at percentages is blowing people's minds.

A post on Reddit posed the question 'What's a little-known but obvious fact that will immediately make all of us feel stupid?'.

One of the replies which has since gone viral online simply stated: "Percentages are reversible. 8% of 25 is the same as 25% of 8 and one of them is much easier to do in your head."

So if were put on the spot and told to work out 16 per cent of 25 you might struggle. But 25 per cent of 16 is a lot easier for our little brains to handle.

And people are wondering how they've made it this far in life without knowing.

One replied: "I am tired. My first thought was bulls***, if that's true then 10% of 1 would be the same as 1% of 10... OMG."

A second wrote: "That I didn't think about this, makes me question my sanity."

Another said: "I am now big brain."

Turns out every day is still very much a school day. Here's a few more replies to the same question as a little Friday treat:

There is no N in the word restaurateur. Penguins swim faster than Michael Phelps. The plural version of cul-de-sac is culs-de-sac. British cows moo in regional accents.