assign page-number-citation to a variable

Hi everyone,

I have a requirement to show the total number of pages for each section at
the beginning of a report. There are 3 sections and I can put an id in
each section. I can also use page-number-citation to get the last page
number for that section. But I need to do some calculations on the page
number ( i.e. section one page number minus section 2 page number). Is it
possible to set a variable with the value of page-number-citation ?

thanks in advance

Anu.