What are the two methods of writing a set?

The two methods of writing a set are the roster method and the set-builder notation. In the roster method, a set is listed explicitly with its elements enclosed in curly braces, such as {1, 2, 3}. In set-builder notation, a set is described by a property that its members satisfy, often in the form {x | condition}, such as {x | x is an even number}.