In math, what lists can be summed into series?

More Questions:

To make beer, what is barley normally made into?

What Bruins and Rangers legend founded the Tampa Bay Lightning in 1991?

In what sport are the Beaters in charge of batting away the Bludgers?

What John Steinbeck novel gets its title from a lyric in "The Battle Hymn of the Republic"?

Which US state is home to White Sands National Monument?

The Gorbals is a district of which city?

What city's buildings include the John Hancock Center and the Amoco Building?

What's the real name of the Gary Glitter track often called "The Hey Song"?

Peter Perfect drove the Turbo Teriffic in which cartoon?

In The Simpsons, who developed a serious slot-machine gambling problem?

Whose debut solo album was entitled "Schizophonic"?

Why were Julius and Ethel Rosenberg executed in 1953?

Who preceded Georges Pompidou as French President?

What number is represented by "D" in Roman numerals?

Who says, "Th-th-th-that's all folks!"?