To perform calculations, add arithmetic operators that evaluate hierarchical document nodes. You can add arithmetic operators to XPath expressions in the Input, Condition, or Output fields of a mapping statement.

The following table describes XPath arithmetic operators that you can use in XMap expressions:

XPath Expression	Description
|	Selects two node sets in context. For example, the predicate expression "//book | //cd" returns a node set with all book and cd elements.
+	Adds the elements. For example, the predicate expression "1+2" returns 3.
-	Subtracts the elements. For example, the predicate expression "2-1" returns 1.
*	Multiplies the elements. For example, the predicate expression "2*1" returns 2.
div	Divides the elements. For example, the predicate expression "6 div 3" returns 2.
=	Selects the elements that equal the expression. For example, the predicate expression "cost=1.50" returns true if the cost is 1.50, and false if the cost is 1.60.
!=	Selects the elements that are not equal to the expression. For example, the predicate expression "cost!=1.50" returns true if the cost is 1.60, and false if the cost is 1.50.
<	Selects the elements that are less than the expression. For example, the predicate expression "tax<1.50" returns true if the tax is 1.00, and false if the tax is 1.50.
<=	Selects the elements that are equal to or less than the expression. For example, the predicate expression "tax<=1.50" returns true if the tax is 1.50, and false if the tax is 1.80.
>	Selects the elements that are greater than the expression. For example, the predicate expression "tax>1.50" returns true if the tax is 1.90, and false if the tax is 1.50.
>=	Selects the elements that are equal to or greater than the expression. For example, the predicate expression "tax>=1.50" returns true if the tax is 1.50, and false if the tax is 1.00.
or	Selects the elements that can satisfy one or more conditions. For example, the predicate expression "tax=1.50 or tax=1.70" returns true if the tax is 1.50, and false if the tax is 1.00.
and	Selects the elements that can satisfy all the given conditions. For example, the predicate expression "price>1.00 and price<1.90" returns true if the price is 1.50, and false if the price is 1.00.
mode	Performs division and provides the remainder. For example, the predicate expression "3 mod 2" returns 1.