Yes, you can do this easily.
Here is what it looks like running:
Here is the question design view:
For the help text, you enter the following:
Code:
Total Now = {sum(self.sq_now)}
Total Future = {sum(self.sq_future)}
and this expands internally to look like this:
Here is the actual question as a .lsq file
The Expression Manager documentation explains how to use the
self variable in more detail.