The world is lost: no one can agree on the answer to this simple calculation.

Multiplication and division,
then addition and subtraction.
Always from left to right when they are at the same level.

Step by step
We begin, therefore, with multiplication and division:

3 × 3 = 9
3 ÷ 3 = 1

The expression becomes:

9 − 1 + 3

Next, we calculate from left to right:

9 − 1 = 8
8 + 3 = 11

Final result: 11

Why so many mistakes?
Many people make this classic mistake: