The formula that works out your age and shoe size has people stumped. Picture: iStock

Basically, by taking your shoe size, multiplying it by 5, adding 50, multiplying that answer by 20, adding 1015 and then subtracting the year you were born, you should land on your shoe size and age.

Ahhh the magic of mathematics.

The magic of maths has once again broken the internet. Picture: Youtube/Goodwill Hunting.Source:YouTube

There are a few variables, in that the equation won’t work if you’ve already had your birthday in 2016, or you have a half shoe size (instead of 5, multiply your shoe size by 50 instead).

So, how does this fabulous formula actually work, and land on the correct shoe and age every time?

According to Professor Geoff Prince, director of the Australian Mathematical Sciences Institute, there’s sadly no real ‘magic’ in this mathematical trick.

“It’s actually a formula, and the 1015 is a real giveaway to how the answer is resolved,” Professor Prince told news.com.au.

“If you were to put the formula in to brackets, so (SHOE SIZE x 5 + 50) x 20 + 1015 — BIRTH YEAR, and break it down, you will actually get 100 x shoe size + age.

“If your birthday has already passed this year, change the 1015 to 1016 and you’ll get the age you’re turning in 2016, as well as your shoe size.”

Sadly, the formula is hardly ‘magic’. Picture: iStock.Source:istock

As for the ‘magic’, these formulas are actually quite easily to generate when put in the right hands.

“The cleverness is making sure the shoe size is multiplied by a big enough number that it comes first in the final answer,” Prof Prince said.

“So by multiplying your shoe size by 100, 1000 or 10,000, the shoe size will lead the answer, which is clever.

“The way the formula was constructed kind of hides everything, and it really is quite easy to make these kinds of equations up.

“For example, I could cook up a formula that reveals your height and weight in 5 minutes if I put my mind to it,” Prof Prince laughed.