It’s fair to say that for a lot of folks out there, math class was a serious struggle throughout most of school. (It was pretty much a losing battle after multiplication tables for this writer).

A recent tweet is blowing not just the minds of the math handicapped but legitimate math teachers as well. This may just be the only time that the internet has been excited over a math lifehack, so pay attention.

Percentages are one of those things that so many people struggle to figure out in their head — hence the reason every phone has a calculator. It’s probably safe to assume that 90 percent of society would be either horrendously undertipping or gloriously overtipping at restaurants without them.

Say you wanted to calculate 4 percent of 75. Without using a calculator this would very possibly send a lot of us into a mental sweat.

Math smartypants Ben Stephens, tweeted out a very simple trick. To borrow from Missy Elliot, simply “flip it and reverse it.”

Fascinating little life hack, for doing percentages:

— Ben Stephens (@stephens_ben) March 3, 2019

x% of y = y% of x

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.

## The internet demanded to know why they didn’t learn this math hack in school.

Using this approach it’s pretty obvious that the answer is three. It’s not crazy easy 100 percent of the time, but it certainly comes in handy quite a bit as Stephens demonstrated a few more examples.

“18% of 50 feels hard to calculate,” he wrote, and he is right it does at first glance. “But 50% of 18 is a doddle, right?”

Raise your hand if you shouted out “It’s 9!” Don’t you feel a little bit like a math genius and suddenly very disappointed in every math teacher you’ve ever had and the American education system at large?

Those of us who studies basic arithmetic at school are scratching our heads as to why this is a revelation 🤷♀️. Next you’ll be telling us that x+y = y+x and that xy = yx

— Ozoda (@OzodaM) March 5, 2019

This sounds like something everyone should ideally have known in high school but I’m today years old when I realized I can’t think in even basic math

— Sandhya Ramesh (@sandygrains) March 5, 2019

GGGAAAHHHHHHHHH EVERY TEACHER I EVER HAS FAILED ME, AND I DON'T MEAN MY GRADES

— The Power Principle (DIRECTOR'S CUT) (@NewMutant) March 5, 2019

This guy might want to have a few words with his English teacher as well.

## Yes, there were even some math folks out there who admitted to not knowing about this trick.

Have a degree in Applied Mathematics and never knew that. 🤔

— Kamal | كمال | ⴽⴰⵎⴰⵍ 🇩🇿🇬🇧🇫🇷🇲🇹 (@DjaidaouiKamal) March 8, 2019

There were, of course, a few who had to show some snark and act like the math hack was no big deal.

If 18 x 5 or 4 x 75 feels hard to calculate in your head, you probably weren't that good at maths. But yes, handy swap trick in general…

— Homer J (@KpunToN00b) March 5, 2019

Now if anybody out there on the interwebs has an equally simple hack for 11th-grade trigonometry, please do share.

My calculator just blew up

— Nigel Daniel (@Nobbydaniel8) March 11, 2019

*Header photo via Wikipedia Commons*