FB 1.5 (I am thinking I need 2.x to get what I need)

I have two select statements that I need one some from. This gets me two values:

select PI.Balance from PersonInfo PI where PI.Person_ID = 154
union
select sum(PAI.Balance) from PersonActInfo PAI where PAI.Person_ID = 154

but I need one value-the some of those two.

Can that be done in FB 1.5?

Ed Dressel