XPath includes five functions that operate on numbers:
floor(number) returns the greatest integer smaller than the number
ceiling(number) returns the smallest integer greater than the number
round(number) rounds the number to the nearest integer
sum(number) returns the sum of its arguments
format-number(number, format-string)
returns the string form of a number formatted according to the specified format-string as if by Java 1.1's
java.text.DecimalFormat
class