Union
$$A \cup B =$$
{ air, earth, fire, question, read, recite, review, survey, water }
Symmetric Difference
$$A \ominus B =$$
{ air, earth, fire, question, read, recite, review, survey, water }
Difference
$$A - B =$$
{ air, earth, fire, water }
Difference
$$B - A =$$
{ question, read, recite, review, survey }
Cartesian Product
$$A \times B =$$
{ (air, question),
(air, read),
(air, recite),
(air, review),
(air, survey),
(earth, question),
(earth, read),
(earth, recite),
(earth, review),
(earth, survey),
(fire, question),
(fire, read),
(fire, recite),
(fire, review),
(fire, survey),
(water, question),
(water, read),
(water, recite),
(water, review),
(water, survey) }