Determine if the following is a set. If not, why not? {2, 4, 6, 8. . .}
Answer
This is a set—the set of all even natural numbers, in fact.
Example 2
Determine if the following is a set. If not, why not? {5, 3, 17}
Answer
This is a set. No one said the things in a set had to be in any sort of order. If someone did tell you that, we suggest that you unfriend them on Facebook.
Example 3
Determine if the following is a set. If not, why not? {Fred, James, Luisa}
Answer
This is a set. It's a set of names. Possibly the names of the people who told you the things in a set had to be in a certain order.
Example 4
Determine if the following is a set. If not, why not? (1, 2, 3)
Answer
This is not a set, because it's written with parentheses instead of curly brackets. Sneaky, sneaky.
Example 5
Determine if the following is a set. If not, why not? {{1}, {2}, {3}, . . .}
Answer
This is a set. Each "thing'' in the set is a set containing a single number. It's like having a roomful of people who are all loners and refuse to socialize with one another. Sounds like some party.
Example 6
Determine if the following is a set. If not, why not? {7, {3}, 5, 6
Answer
This is not a set. This is mathematical gibberish, because there's an opening bracket but no closing bracket. It's like a sentence without a