Please help settle the argument raging in my work place:

18 - 6 / 2 + 4 x (7 - 2) = ??

50

18-3+4x5=15+20=35

groetjes,
Mirella

Yeah but no but yeah.

See shouldn't you do addition before subtraction and therefore get 18 - 23 = -5 ?

thats called order of operations

yes, addition and substraction are equally strong. Like division and multiplication.

groetjes,
Mirella

No, only if you'd written
18 - (6 / 2 + 4 x (7 - 2)) = ??
instead of
18 - 6 / 2 + 4 x (7 - 2) = ??

groetjes,
Mirella

But if they are equally important couldn't the answer be 35 or -5?

No. What you do with the 20 is substract them, while there is a + before them. The only way to manage that is with the hooks, as I showed before.

groetjes,
Mirella

Nope, you go left to right

So if you have addition and subtraction you work left to right?

here are some variations:

18 - 6 / 2 + 4 x (7 - 2) = 35

18 - 6 / 2 = 35 - 4 X (7-2)
18 - 3 = 35 - 20
or
18 = 35 + 6/2 - 4 X (7-2)
18 = 35 + 3 - 20

and lots more. That's the good thing about equalisation: there's always just one answer

Here's the same one from right to left, because that doesn't really matter:

(7-2) x 4 - 6/2 + 18
it's still

5x4 - 3 + 18 = 17 + 18 = 35

groetjes,
Mirella

OK now I get it.

Thanks.

Even though you didn't give the answer I wanted.

http://en.wikipedia.org/wiki/Order_of_operations

What I always liked was when you have these large puzzles and you can solve them just by shuffling it around and striping things away against each other.
It all starts so simple: one sides equals the other side of the =, and when they move to the other side, the + changes into -

3+4=7
3=7-4
-7=-4-3
-7+4=-3
-7+4+3=0

and more fun like that (insert semi-nerd smiley here )

Next time your answer will be the right one, because now you know . I was always in fights about calculations of probability, even with my teacher. With her, my marks dropped from very good to just enough to pass.

groetjes,
Mirella

It's all about BODMAS

B Brackets first
O Orders (ie Powers and Square Roots, etc.)
DM Division and Multiplication (left-to-right)
AS Addition and Subtraction (left-to-right)

Fuckin Aussies, it's PEMDAS (please excuse my dear aunt sally)
parenthesis
exponents
multiplication
division
adddition
subtraction

The problem was I was using

B
O
D
M
A
S

and not

B
O
DM
AS

We were always taught BEDMAS