Possible Duplicate:
What is 48÷2(9+3)?
Please, look at the picture?
Which calculator shows true result and how to prove achieved result?
Possible Duplicate:
What is 48÷2(9+3)?
Please, look at the picture?
Which calculator shows true result and how to prove achieved result?
Despite every personal belief, a notation like $a/b(c+d)$ is ambiguous. At school I learned that this should be $ \frac{a}{b}(c+d), $ but even in research papers somebody could read $ \frac{a}{b(c+d)}. $
when two operations have same precedence, then the operations are done from left to right.So here, division is done first and then multiplication.This is just a convention.Without this, this expression is ambiguous.
The reason why calculators are giving different results is because one is calculating,
$\frac{6}{2\cdot(2+1)} = 1$
while the other is calculating,
$\frac{6}{2}\cdot(2+1) = 9$
Depending on what you want to calculate, you could obtain different answers.