Adding calculation from different reports

Content

Is it possible to add the total calculations from 3 reports in a dashboard to a 4th report?

For ex:

Report 1 has total = x; report 2 has a total = Y, report 3 has a total = Z

The 3 reports are part of a dashboard

I would like to present a calculation X+Y+Z somewhere in the dashboard

any ideeas

thx

dan