Every so often it’s good to exercise your brain with a math problem or two that forces you to recall principles you learned decades prior.
As elementary as it might feel, you’d be surprised how easy it is to be stumped by a seemingly simple equation.
This problem, posted on X, in particular may be challenging for even the best of mathematicians. Can you solve it without a calculator?
5+5 x 5+5
At first it may look easy, but it’s important to go back to basics before diving in head first.
The acronym PEMDAS can be handy when solving a sum like this one. Its letters spell out the order in which you should solve complex equations.
The ‘p’ stands for parenthesis, then exponents, multiplication and division, and then adding or subtracting.
Now, give it a try for yourself.
PEMDAS is a helpful tool for solving complex equations like this one
Using the rules of PEMDAS, the first step is to solve the sum at the center of the problem, no matter how unnatural it may feel:
5 x 5 = 25
Now, the problem reads:
5+25+5
With simple addition from left to right, the final sum is easy:
5+25=30
30+5= 35
How did you do?
It’s important to start this sum in the center, no matter how unnatural it may feel
If you couldn’t solve it, don’t worry, there are a few common mistakes that could have led to a different answer.
The first, is adding on both sides before multiplying in the middle.
Adding first on the left:
5+5=10
Making the problem:
10×5+5
Then, adding on the right:
5+5=10
That makes the solution:
10×10=100
Unfortunately, that method totally ignores the rules of PEMDAS, rendering the answer incorrect.
When solved correctly, the equation comes out to 35
Another easy error would be to solve from left to right, which may feel natural at first.
5+5=10
That leaves:
10×5+5
Then:
10×5=50
Which would make the solution:
50+5=55
But PEMDAS is a fool-proof way to guarantee the right answer every time and tease your brain with all-too-familiar math tricks.
