Question

The following code outputs “3”. I was expecting “1”.

echo $resultado."\n"; // show 2
$valor = $resultado * ($resultado - 1 / 2);

echo $valor."\n"; // show 3, and should be 1

Why does this happen?

Answer 1

Because the division 1 / 2 takes precedence in the order of operations. So you have really have this expression:

$resultado * ($resaltudo - (1 / 2))

You should add parenthesis to be:

$resultado * (($resaltudo - 1) / 2)

to get the answer you want.