Adding decimal values is just like adding whole numbers. For the most part you can just pretend that the decimal point isn't even there. Here are a few examples:
3.55 5.83
+ 4.75 + .19
-------- -------
8.30 6.02
3.47 3.64
+ 2.35 + 3.37
-------- --------
5.82 7.01
You can carry right straight past the decimal point as if it wasn't even there.
Now you get to try a few for yourself.