it is a very simple pojo java class. two method return different type numeric value can't use symbol such as "*","+", and so on. a method and a constant value can work, such as a.getAge() + 2.0, and the getAge() method return a integer. so I resolve this problem by use 1*a.getAge() + a.getIncome(), that expression work correctly. -- View this message in context: http://drools.46999.n3.nabble.com/Drools5-3-can-t-support-double-int-tp40... Sent from the Drools: User forum mailing list archive at Nabble.com.