sub-formula
 Known as an intermediate or nested formula. A formula that is
		used within another formula. You add a sub-formula in the 
		Item Lines tab of the 
		Formula form by entering a formula code in the 
		Formula Code column. After the
		sub-formula has been added, you can adjust its quantities appropriately for the
		formula it has been brought into. The sub-formula can have a manufacturing item
		code associated with it, but it is not required.