At first glance, it looks like a simple math problem. Four times the number 11, a few basic operations… and yet. This little math challenge fools thousands of people every day, including some very sharp minds. So, before you tell yourself that math was better in high school, give it a try. The answer might surprise you—in one way or another!
Why is this calculation so misleading?
Imagine yourself with this equation: 11 – 11 × 11 + 11. Your brain, true to form, will naturally read from left to right. A bit like when you read a message or a recipe. The result: you solve 11 – 11 first, you get 0, you multiply by 11… and you arrive at a completely wrong answer.
That's precisely where the trap lies. This reflex of linear reading makes us forget a fundamental rule, learned in primary school. And in everyday life, we don't really have the opportunity to review it!
The golden rule that we always forget
Everything hinges on the order of operations . In France, this is taught from middle school onwards: multiplication and division always come before addition and subtraction. Unless otherwise indicated in parentheses, of course.
To put it simply, here is the order to follow:
– Parentheses first – Exponents and powers second – Multiplication and division (from left to right) – Addition and subtraction (from left to right)
It's not a matter of genius. It's simply a matter of method. And the good news is: you can figure it out in seconds!
We solve it together, step by step.
Let's start again calmly. The operation is: 11 – 11 × 11 + 11
Step 1 — Multiplication first: 11 × 11 = 121
Step 2 — The equation becomes: 11 – 121 + 11
Step 3 — We solve from left to right: 11 – 121 = –110
Step 4 — We finish: –110 + 11 = –99
The correct answer is therefore -99 .
So, were you right?
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