Learning XPath Expressions By Examples

What is the title of chapter 2?

//chapter[2]/title
//chapter[position()=2]/title
//chapter[@id="2"]/title
//chapter[@id='2']/title

How much does this book cost?

concat(/book/price, " (", /book/price/@currency, ")")
concat(ceiling(/book/price), " (", /book/price/@currency, ")")
concat(floor(/book/price), " (", /book/price/@currency, ")")
concat(round(/book/price), " (", /book/price/@currency, ")")
concat(substring-before(/book/price, "."), " dollars and ", substring-after(/book/price,"."), " cents")

Select all even-numbered chapters

/book/chapter[position() mod 2 = 0]