When we quickly read a calculation like 11 – 11 × 11 + 11, our brain tends to read from left to right, solving each step in the order it appears. This is a common mistake! This reflex often makes us miss a fundamental rule in mathematics: multiplication always comes before addition and subtraction, unless parentheses change the order.
That's precisely what makes this kind of challenge so interesting. It's not about being a "math genius," but simply about remembering the correct method. A welcome—and rather fun— refresher !
The order of operations, that unsung hero of our daily lives
Remember: starting in middle school, we learn the famous order of operations. It has different names depending on the country (PEMDAS, BODMAS…), but the principle remains the same:
- Parentheses
- Exponents (or powers)
- Multiplication and division, from left to right
- Additions and subtractions, also from left to right
Don't panic, here we only have three operations to manage: multiplication, subtraction, and addition. But it is precisely this deceptive simplicity that makes the exercise misleading.
Let's solve it together, step by step.
Let's take our time. Here's the procedure:
11 – 11 × 11 + 11
We begin with multiplication:
11 × 11 = 121
The calculation therefore becomes:
11 – 121 + 11
Next, we solve the remaining operations from left to right:
11 – 121 = -110
Then,
-110 + 11 = -99
The result
The correct answer is therefore: -99
And you, did you find it?
If so, congratulations! You have a solid grasp of mathematical logic and a good memory of your school foundations. If not, no worries: this kind of challenge is there to remind us of rules we sometimes forget in everyday life.
And let's be honest, it's not every day you have to solve this kind of equation between text messages or while preparing dinner . But it's an excellent exercise to wake up your brain, stimulate your memory… and impress your friends and family at the next happy hour quiz !
These little challenges are good for our brain
Beyond their playful aspect, mathematical puzzles are a real workout for our minds. They force us to slow down, to concentrate, to organize our thoughts. A bit like mini yoga for the mind , in short!
So why not make it a ritual? A little challenge each day to keep your mind sharp, while having fun. Share it with your children, partner, or colleagues for a slightly more original coffee break.
What if the best brain exercise... was simply playing with numbers?
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