Math
posted by Sami .
how do you evaluate these numbers?
/48//20/
/51/
I have looked every where and I need help please.

Basically, the number inside the / / is always positive. Only if it has a negative sign on the OUTSIDE, is it negative. The / / means "absolute value" which is simply how far away from 0 on a number line the number is. So, /48/ is 48 spaces from 0, so it's value is 48.
Hope this makes sense! 
does it look like this?
│48│  │20│
if so, you are dealing with "absolute value".
it simply means take the positive value of the number you are dealing with, so ...
│48│  │20│
= 48  20
= 28
and │51│
=  51 
By take away the numbers.