QV17 Subtract number from variable - set analysis expression

some times we need to subtract or add the number from the variable value. So i am posting this how we can subtract the number from set analysis expression in qlikview.

from this post we can learn
- how to use variable in set analysis
- how to subtract number from variable

Let have a look upon the matter
I have emp table and if you see the hiredate year variation from 1980 to 1987 as you can see in your below image.

 

I also have created calendar as in post 

http://j4info.blogspot.in/2014/09/qv16-create-calendar-dimension-using.html

after creation of calendar we have below data model.

After reload we have added below objects in the existing sheet. 

current selection is 1981 and variable vMaxYear store 1981 value in it. chart have below dimension
DEPTNO
HIREDATE

and expression :
chart1 - Sum ({$(=$(vMaxYear)-1)}>}SAL)

 will show the data of employees whose HIREDATE lie in the year 1980.

chart2 - Sum ({}SAL)
 will show all data, irrespective of any date selection.