Having one, means having something to follow. Once you question it, it means having none. People seek it, but some do and some don’t find it. What is it?

There are two boys at an international math contest in December 2013; one is British and one is American. They both write their names, the date, and their answers on the paper. The only problem is that they both have the same name and the papers cannot be told apart.

What is the date?

What word doesn’t belong in this group?
That, hat, what, mat, cat, sat, pat, or chat?