Simple Math on a Pivot Table

Summary

I need some help with some math that I might be overcomplicating.

Content

I have created a pivot table that groups employees into temporary, seasonal and regular table and within the tables, I have separated the employees into groups based on the most recent action code: 'layoff', 'leave of absence', 'other (includes all actions that an active employee could have)'.

 I would like to produce a final total for each group (temporary, seasonal and regular) that showcases the amount of 'active' employees per group which I would ultimately get by: (total amount of seasonal employees - (seasonal layoff employees - seasonal leave of absence employees) )