Need Serious Math help, 6÷2(1+2)=? Look at description please

The way you have WRITTEN the equation.. the answer is 1.

assuming you mean : 6/ (2*(1-2))

Now to get 9 >> you have to assume the question statement is asking for: (6/2)*(1+2)

It depends on the question statement. THere is no magic way your friend got 9.

And what exactly does this have anything to do with Calculus?

Its a simple numerical computation.

There is no point in obsessing over this. There are far more important mathematic concepts you can use your time to understand other than mathematical semantics.

Mathematic regulations clearly state that the order of operations is as follows:
terms inside parenthesis
exponents and roots
multiplication and division
addition and subtraction

So first you do the addition between brackets (1+2)=3
The you have 6/2*3
Since multiplication and division is on the same level, according to regulations, you calculate from left to right, so first you do 6/2=3 which leave the multiplication 3*3 which is 9. 9 is the only correct answer if you follow mathematical regulations.

you add 1 and 2 first which gives you 3
you divide the 6 and 2 which gives you 3
3x3=9

in PEMDAS (Parentheses exponents multiplication division addition subtraction)
YOU FORGOT FOR MULTIPLICATION AND DIVISION YOU READ LEFT TO RIGHT(:
which means in this problem you would divide before you multiply

Everyone who says it's 9 is WRONG and need to go back to school.

By PEMDAS (parentheses, exponents, multiplication, division, addition, subtraction) We must work out the parenthesis then multiplication then division.