sign math block?

how can i sign something for example...
sign(-12) = -1
sign(35) = 1
sign(0) = 0
sign(99999999999999999) = 1
sign(-99999999999999999) = -1

If you have non-zero numbers, you can divide the number by it's own absolute value to get the sign. Division is clunky though, and if you just create your own custom block (function) you can easily use If/Else statements to do this.
Additionally, doing so would let you decide what to do with zeros, instead of dividing by zero and crashing.

i'm not sure how custom blocks work though :/

Just create 2 number attributes: one for your number to be checked (CheckSign), one for your Sign-check (SignOutput)

If CheckSign is > 0
Set SignOutput to 1
If CheckSign = 0
Set SignOutput to 0
If CheckSign < 0
Set SignOutput to -1