XPath also has a sum function, which will take the contents of the matching nodes, convert them to numeric values, and return the sum of those values.

XPath也有一个sum函数，它以匹配节点的内容作为参数，将这些参数转换成数值，并返回这些值的和。

youdao

East Hampshire began to pioneer a scheme known as "private provision", which means public houses, restaurants or churches agree to provide toilets for the general public in return for an annual sum from the council.

BBC: Save our loos plea

The church is offering a four-figure sum of money for information that leads to the return of the jewellery.

BBC: Ring

Currently run by Severn River Crossing Plc, the bridge will return to public ownership when the firm has collected a fixed sum of money from tolls, expected to be around 2017.

BBC: Welsh Affairs Select Committee