Maybe an example helps.
A=1
B=3
If you do
C=A+B
D=B-A
you end up with
C=4.0000
D=2.0000
Now if you do
Location=C,D
you get
Location=4,2
which equals
Left=4
Top=2
Tada, you have your integers and can assign them to something else, eg
IconSize=Left
This allows you to assign the output of the mathematical operation A+B to, for example, IconSize, which you cannot do directly because of the decimal point.