Ok, it says -(-10) is 10, which I get, but why does -|-5.2| = -5.2? I thought || were the same as ()
The $\displaystyle |x|$ is the modulus of $\displaystyle x$ and it is always positive so...
$\displaystyle -|-5.2| = - |5.2| = -5.2$
Whereas $\displaystyle (x)$ are just brackets and do not change the value of $\displaystyle x$ inside so...
$\displaystyle -(-10) = - - 10 = 10$ (It's a minus of a negative number so makes it positive).
You don't get square brackets unless you want to show a bracket of a bracket in which case a square bracket looks neater so...
e.g. $\displaystyle [ (x + 2) (x - 2)] - 2$
(In which case you are saying, find the value of the brackets first then do the arithmetic outside the square bracket).
A square bracket doesn't change the value of the number so it is the same as $\displaystyle (x)$ curvy bracket.
EDIT: It is not the same as modulus = $\displaystyle |x|$