statistics help

Hi, I got a question, hope you guys can help me. is it possible to create a formula which subtracts let's say for example the total number from worksheet2 minus the total number from worksheet1. my boss gave me this requirements for reporting and I don't know if its possible to do in excel

4) Difference to previous run in statistics (counts)
5) Difference to previous run in individual test cases (e.g. which failed this time that 
passed in previous round & vice versa)
6) Number of defects found&reopened&closed in this round

please post your workbook